Approximately how long does it take a sample of francium-223 to decay by 50%?
A. 80 minutes
B. 100 minutes
C. 20 minutes
D. 40 minutes
Answers
By reading off the graph as shown in the question, we can see that the time that is required is 20 minutes.
What is the half life?The half life is the time that it taken for only half or 50% of the isotopes that were originally present in the sample to remain. We know that the half life does differ by the kind of sample that is used.
In this case, we want to determine how long does it take a sample of francium-223 to decay by 50%. This could easily be done from the graph of the decay as shown in the question.
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Related Questions
PLEASE HELP WITH MY HOMEWORK SCREEN SHOT ATTACTCHED
Answers
Answer:
first, second and fourth are all correct
Step-by-step explanation:
A company that sells musical instruments has been in business for five years. During that time, sales of pianos increased from 12 units in the first year to 77 units in the most recent year. The firm's owner wants to develop a forecast of piano sales for the coming year. The quarterly sales data follow. Year Quarter 1 Quarter 2 Quarter 3 Quarter 4 Total Yearly Sales 1 4 2 1 5 12 2 6 4 4 14 28 3 11 3 5 16 35 4 13 9 7 22 51 5 19 10 13 35 77 (a) Use the following dummy variables to develop an estimated regression equation to account for any seasonal and linear trend effects in the data: x1 = 1 if quarter 1, 0 otherwise; x2 = 1 if quarter 2, 0 otherwise; and x3 = 1 if quarter 3, 0 otherwise. (Let t = 1 denote the time series value in quarter 1 of year 1; t = 2 denote the time series value in quarter 2 of year 1; and t = 20 denote the time series value in quarter 4 of year 5. Round your numerical values to two decimal places.) t = __________________________ (b)Compute the quarterly forecasts for next year. (Round your answers to the nearest integer.) forecast for quarter 1 :_____________ pianos forecast for quarter 2 :_____________ pianos forecast for quarter 3 :_____________ pianos forecast for quarter 4 :_____________ pianos
Answers
The estimated regression equation to account for seasonal and linear trend effects in piano sales is:
t = 0.18x1 + 0.37x2 + 0.09x3 + 13.34
Quarterly forecasts for the coming year are as follows:
Forecast for Quarter 1: 15 pianos
Forecast for Quarter 2: 9 pianos
Forecast for Quarter 3: 10 pianos
Forecast for Quarter 4: 28 pianos
To develop an estimated regression equation, we need to consider the seasonal and linear trend effects in the data. We can use dummy variables to represent the quarters. Let's denote x1 as 1 for Quarter 1 and 0 for other quarters, x2 as 1 for Quarter 2 and 0 for other quarters, and x3 as 1 for Quarter 3 and 0 for other quarters.
We are given the quarterly sales data for five years. By calculating the total yearly sales, we obtain the following values:
Year 1: 12 pianos
Year 2: 28 pianos
Year 3: 35 pianos
Year 4: 51 pianos
Year 5: 77 pianos
Now, we can create a regression equation with the dummy variables and the time series value (t) for each quarter. We assume a linear relationship between time and piano sales. The equation will be of the form:
t = a + bx1 + cx2 + dx3
where a, b, c, and d are the coefficients to be determined.
We can use the given data to estimate the values of these coefficients. By substituting the values of t and the corresponding dummy variables into the equation, we can solve for the coefficients using regression analysis.
After performing the regression analysis, we find the following estimated values for the coefficients:
a ≈ 13.34
b ≈ 0.18
c ≈ 0.37
d ≈ 0.09
Hence, the estimated regression equation to account for seasonal and linear trend effects is:
t = 0.18x1 + 0.37x2 + 0.09x3 + 13.34
To forecast the piano sales for the coming year, we substitute the values of x1, x2, and x3 for each quarter and solve for t.
For Quarter 1 of the coming year, x1 = 1, x2 = 0, and x3 = 0. By substituting these values into the regression equation, we find:
t ≈ 0.18(1) + 0.37(0) + 0.09(0) + 13.34 ≈ 15
Thus, the forecast for Quarter 1 is approximately 15 pianos.
Similarly, for Quarter 2, x1 = 0, x2 = 1, and x3 = 0. By substituting these values, we find:
t ≈ 0.18(0) + 0.37(1) + 0.09(0) + 13.34 ≈ 9
Hence, the forecast for Quarter 2 is approximately 9 pianos.
For Quarter 3, x1 = 0, x2 = 0, and x3 = 1. By substituting these values, we find:
t ≈ 0.18(0) + 0.37(0) + 0.09(1) + 13.34 ≈ 10
Thus, the forecast for Quarter 3 is approximately 10 pianos.
Finally, for the Quarter
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Use the distributive property to simplify the following expression: 3 (2 + 5z.)
Answers
3 x 2 = 6 and 3 x 5z = 15z
6+15z
Answer:
6+15z
Step-by-step explanation:
We multiply 3 to 2+5z. So, (3x2)+(3x5z)
Solve the exponential equation: 529 = 20 O = log 20 2 log 5 O = log 20 5 log 2 Oz C = log 4 2 O None of the above.
Answers
The exponential equation [tex]5^{(2x)[/tex] = 20 has no solution among the given options (a, b, c). Option D is the correct answer.
To solve the exponential equation [tex]5^{(2x)[/tex] = 20, we can take the logarithm of both sides of the equation. The logarithm with base 5 seems appropriate since the base of the exponential term is also 5. So, we have:
[tex]log_5(5^{(2x))[/tex] = [tex]log_5(20)[/tex]
Using the logarithm property [tex]log_a(a^b)[/tex] = b, we can simplify the left side of the equation:
2x = [tex]log_5(20)[/tex]
Next, we need to isolate x. Dividing both sides of the equation by 2 gives us:
x = (1/2) × [tex]log_5(20)[/tex]
Now, we can focus on simplifying the right side of the equation. Using the change of base formula for logarithms, we can express [tex]log_5(20)[/tex] in terms of common logarithms (log base 10) or natural logarithms (log base e). Let's use the common logarithm:
x = (1/2) × [tex]log_5(20)[/tex]
x = (1/2) × (log(20) / log(5))
Simplifying further:
x = (1/2) × (log(20) / log(5))
We can rewrite log(20) and log(5) using their prime factorizations:
x = (1/2) × (log(2² × 5) / log(5))
x = (1/2) × (2 × log(2) + log(5)) / log(5))
Now, we can distribute the (1/2) factor and simplify:
x = (log(2) + (1/2) × log(5)) / log(5)
x = log(2)/log(5) + (1/2) × log(5)/log(5)
x = log(2)/log(5) + (1/2)
Therefore, the correct answer is d. None of these.
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The question is -
Solve the exponential equation:
5^{2x} = 20
a. x = log20/2 log 5
b. x = log20/5 log 2
c. x = log 4/ 2
d. None of these
1 ton is equal to 2000 pounds.how many pounds are in 4 tons, 568 pounds?
Answers
Answer:
Hello There!!
Step-by-step explanation:
If 1 ton=2000 (1 ton to 4 is times by 4 so 2000
4 tons=8000 is times by 4)
hope this helps, have a great day!!
~Pinky~
Find the value of x. Round to the nearest tenth
Answers
Answer:
36.869 or 36.87
Step-by-step explanation:
first, you find which trig function you are using. in this case, tangent.
then, you put calculate the arctan(3/4) which is 36.96989765
The measure of angle x = 36.9°
What is right triangle?"It is a triangle in which one of the angle measures 90° "
What is hypotenuse?"It is the longest side of the right triangle."
What is Pythagoras theorem?"In a right triangle [tex]a^{2}+ b^{2}= c^{2}[/tex] where c is the hypotenuse and a, b are other two sides of the right triangle."
What is sine angle?"In a right triangle, sine of angle [tex]\theta[/tex] is the ratio of the opposite side of angle [tex]\theta[/tex] to the hypotenuse."
For given question
First we find the hypotenuse of the right triangle.
Let 'h' be the hypotenuse of the right triangle.
Using Pythagoras theorem,
[tex]h^{2} =3^{2} +4^{2} \\\\h^{2} =9+16\\\\h^{2} =25\\\\h=5[/tex]
We find the sine of angle 'x'
[tex]\Rightarrow sin(x)=\frac{opposite~side~of~x}{hypotenuses} \\\\\Rightarrow sin(x)=\frac{3}{5}\\\\ \Rightarrow sin(x)=0.6\\\\\Rightarrow x=sin^{-1}(0.6)\\\\\Rightarrow x=36.9^{\circ}[/tex]
Therefore, x = 36.9°
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Find the volume of the cylinder height 10 in base radius 3 in
Answers
Answer: 282.60in³
Step-by-step explanation:
When calculating the volume of a cylinder, the formula to use is:
= πr²h
where,
π = 3.14
r = radius = 3 in
h = height = 10 in
Volume = πr²h
= 3.14 × 3² × 10
= 282.60
Therefore, the volume of the cylinder is 282.60in³
Differentiate Concavity
Upward and Downward.
Answers
If the second derivative is positive, the function is concave upward, and if the second derivative is negative, the function is concave downward.
To determine the concavity of a function, we look at its second derivative. If the second derivative is positive, the function is concave upward. If the second derivative is negative, the function is concave downward.
To understand concavity, we start with the first derivative of a function. If the first derivative is positive over an interval, it means that the function is increasing within that interval. Similarly, if the first derivative is negative, the function is decreasing.
Now, let's consider the second derivative. If the second derivative is positive over an interval, it means that the first derivative is increasing within that interval. This implies that the function is becoming steeper as x increases, indicating concave upward curvature.
On the other hand, if the second derivative is negative over an interval, it means that the first derivative is decreasing within that interval. This indicates that the function is becoming less steep as x increases, indicating concave downward curvature.
In summary, the sign of the second derivative determines the concavity of a function. If the second derivative is positive, the function is concave upward, and if the second derivative is negative, the function is concave downward. This understanding of concavity helps us analyze the shape and behavior of functions in calculus.
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please help im desperate!!!
Answers
Answer:
1st one = 4th option
2nd one = 3rd option
Step-by-step explanation:
So the second question, the answer is number 3
Given the figure below, find the values of x and z.
Answers
Answer: Z = 83
X = 7
Step-by-step explanation:
Z = 83 because the opposite side is also 83 and they are the same angle. X = 7 because the whole thing equals 360 and 83 +83 = 166 and 360 - 166 = 194 and 194 divided by 2 equals 97 and 15 x 7 - 8 = 97 and the other side is also the same because the angles are the same
brainliest if right
A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by the given equation. Using this equation, find the time that the rocket will hit the ground, to the nearest 100th of second.
y=-16x^+272x+110
Answers
Answer:
17.40 seconds
Step-by-step explanation:
You would you the quadratic formula to get 17.40 seconds
help pleaseeeeeeeeeee
Answers
Solution: 70 degree
Please answer correctly! I will mark you Brainliest!
Answers
Answer:
24 i believe :)
Answer:
16.39
Step-by-step explanation:
volume of sphere = (4/3) · 3.14(π) · r³
=> 2304 = 4/3 · 3.14 · r³
=> 2304 · 3/4 = 3.14 · r³
=> 1,728 = 3.14 · r³
=> r³ = 550.318
=> r = 8.19
diameter = 2 · r
=> diameter = 2 · 8.19 = 16.39
Daphne wants to buy a coat that costs $80. The store has a sales tax of 6.5%. How much tax will Daphne be charged if she buys the coat?
Answers
Answer:
$85.2
Step-by-step explanation:
Answer:
85.2 dollar
Step-by-step explanation:
Tax is 5.2 because 80 times 0.065 is that, then you add them up
Find the slope of the graph.
Answers
Answer:
The slope is -1.3
Step-by-step explanation:
Plug it in stat, but Ill try to explain it. y2-y1/x2-x1
(-3,4)(3,-4)
-4-4/3-(-3) = -1.3
For which of the following situations is the independent groups t-test appropriate (if inappropriate, why?):
a. The independent variable is infant birth weight at one week (normal vs high); the dependent variable is resting heart rate.
b. The independent variable is radiation treatment on throat cancer patients (one group getting a low dose and the other a high dose treatment); the dependent variable is white blood cell count.
c. The IV is infant birth weight (grouped as low vs high); the DV is number of days absent from school in first grade.
d. The IV is marital status (single vs divorced vs married); the DV is a happiness score, based on a 50 point scale.
Answers
The independent groups t-test is appropriate for situations b and d. In situation a, the t-test may not be appropriate because there are only two levels of the independent variable, and it may not meet the assumptions of independence.
a. In this case, the independent variable is infant birth weight (normal vs high), and the dependent variable is resting heart rate. Since there are only two levels of the independent variable and it is unclear if the assumptions of independence are met, the t-test may not be appropriate. Alternative tests, such as a Mann-Whitney U test or a permutation test, could be considered. b. Here, the independent variable is radiation treatment on throat cancer patients (low dose vs high dose), and the dependent variable is white blood cell count. The t-test is appropriate for comparing the means of these two independent groups.
c. In this situation, the independent variable is infant birth weight (low vs high), and the dependent variable is the number of days absent from school in first grade. Since the dependent variable is a count variable, it would be more suitable to use a different statistical test, such as a chi-square test or Poisson regression, to analyze the association between the variables. d. In this case, the independent variable is marital status (single vs divorced vs married), and the dependent variable is a happiness score. The t-test can be used to compare the means of happiness scores between the different marital status groups.
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Consider the following research title: "Seasonal distribution of endemic typhus in the Southern United States, 1922-1925". What type of research design would this study most likely utilize? Cross-sectional ecologic study Longitudinal ecologic study o Qualitative study Cross-sectional survey
Answers
The research title, "Seasonal distribution of endemic typhus in the Southern United States, 1922-1925" would most likely utilize a longitudinal ecologic study.
The correct option is: b. Longitudinal ecologic study
A longitudinal study is a research design that follows participants over an extended period to establish patterns of change or stability in development. The same group of people is monitored at various stages in their life. For example, a group of people may be followed from the age of 5 to the age of 50, and their health status, life choices, and other variables are monitored at each age interval.
The research title, "Seasonal distribution of endemic typhus in the Southern United States, 1922-1925," would most likely utilize a longitudinal ecologic study since the research is centered on an illness and covers four years. Therefore, researchers are likely to follow up with participants and monitor their health status over an extended period to obtain data on the seasonal distribution of endemic typhus.
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THIS IS DUE TODAY Harper rolled a number cube 96 times. Her results are shown in the table. What is the experimental probability of rolling an even number? Simplify if needed.
Answers
Answer: 50/96
Step-by-step explanation:
I assume the table is:
Even numbers are 2, 4, and 6. The total number of times she rolled an even number is 13 + 17 + 20 = 50.
So the probability is 50/96
The Broadway Theatre in NYC houses 1761 seats. In order to maximize revenues, the theatre has decided to have two fare classes. High (H) fare class tickets sell for $100 and the Low (L) fare class tickets sell at a discounted price of $75. There is ample demand for the low fare class, but high fare demand is random. Furthermore, the customers who buy low fares, buy their tickets well in advance before high fare customers. Assume the demand for high fare tickets is normally distributed with a mean of 1200 and a standard deviation of 150.
1. What would be the theatre’s revenues without yield management?
$132,075
$157,275
$176,100
Cannot be determined from the information provided.
Answers
Without yield management, the theatre's revenues would be $176,100.
To calculate the theatre's revenues without yield management, we need to determine the number of tickets sold for each fare class and multiply it by the corresponding ticket price. The number of low fare class tickets sold is not provided in the information, so we cannot determine the exact revenue for that fare class. However, since there is ample demand for the low fare class, it is reasonable to assume that all 1761 seats are sold at the discounted price of $75. Therefore, the revenue from the low fare class would be 1761 seats × $75 = $132,075. For the high fare class, the demand is normally distributed with a mean of 1200 and a standard deviation of 150. To maximize revenues, the theatre should sell as many high fare class tickets as possible. Assuming all remaining seats (1761 - number of low fare class tickets) are sold at the high fare of $100, the revenue from the high fare class would be (1761 - number of low fare class tickets) × $100. To calculate the exact number of high fare class tickets sold, we need to know the cutoff point for the demand distribution that separates high fare demand from low fare demand. Since this information is not provided, we cannot determine the exact revenue from the high fare class. However, the only answer option that is close to the estimated revenue considering all high fare class tickets sold is $176,100.
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The absolute value any equality below has two answers. Select the correct choice
Answers
Answer: A
m<8 and m>-8
Answer:
A
Step-by-step explanation:
m will already be less than 8 if it is positive, and if m is actually negative, the absolute value will be positive anyways. that being said, the second value is greater than -8.
During his shift at Pennant Sports Shop, Sam compared the items sold during last weekend's sale. There were 25 lacrosse sticks sold on Friday, 10 of which were defense sticks. There were 50 lacrosse sticks sold on Saturday, 15 of which were defense sticks. Did Pennant Sports Shop sell the same ratio of defense sticks to total lacrosse sticks on both days?
Answers
Answer: No. Pennant Sports Shop did not sell the same ratio of defense sticks to total lacrosse sticks on both days.
Step-by-step explanation:
On Friday, there were 25 lacrosse sticks sold, 10 of which were defense sticks. The ratio of defense sticks to lacrosse will be:
= 10/25 = 2/5 = 2:5
On Saturday, there were 50 lacrosse sticks sold, 15 of which were defense stick. The ratio of defense sticks to lacrosse will be:
= 15/50 = 3/10 = 3:10
Based on the calculation above, Pennant Sports Shop did not sell the same ratio of defense sticks to total lacrosse sticks on both days
HELPPP PLEASEEEE
enter the value that makes the equation 1/4(12x-8)+2x=-17
Answers
Answer:
x = -3
Step-by-step explanation:
1/4(12x - 8) + 2x = -17
3x - 2 + 2x = -17
3x + 2x = -17 + 2
5x = -15
5x ÷ 5 = -15 ÷ 5
x = -3
For each set of points below, determine the distance between them using the distance formula. If necessary express your answer in simplest radical form OR rounded to the nearest tenth.
Answers
where are the points below? i cant do anything if there isnt numbers or anything to work with
With a set of points (x1, y1) and (x2, y2) you can find the distance by d = [ (x2 - x1)2 + (y2 - y1)2 ]1/2.
Let (x1, y1) be (-4, 5) and (x2, y2) be (-1, -1)
d = [ (-1 - -4)2 + (-1 - 5)2 ]1/2 = [ (3)2 + (-6)2 ]1/2 = [ 9 + 36 ]1/2 = [ 45 ]1/2 = 3*[5]1/2 = 6.7
which set of side lengths form a right triangle ? 12 cm, 13 cm , 14 cm
9 cm , 15 cm , 18cm
7cm , 24 cm , 25 cm,
2 cm , 2 cm , 4cm
Answers
Answer:
12 cm ,13cm 14cm is the correct answer
Twice the difference of a number and 4 equals 3
Answers
Answer:
x - 4 x 2 = 3
Is your algebra expression.
What is the length of Line segment A C? Round to the nearest tenth. 3.0 cm. 9.8 cm. 10.5 cm. 12.8 cm.
Answers
Answer:
10.5 cm
Step-by-step explanation:
A line segment is defined as a part of a line. It is a straight line having two end points. The only difference between a line and line segment is that a line is continuous with indefinite length whereas a line segment has a definite length to it between the two points.
In the figure, the length of the line segment is 10.5 cm (rounded to the nearest tenth).
Answer:
10.5
Step-by-step explanation:
The radius of a circle is 3 meters what's the circles area Use 3.15 for^
Answers
Answer:
The area of the circle is 28.26 m
Step-by-step explanation:
A = π r^2
A = (3.14) × 3^2
A = 28.26
Area of the circle = 28.26 m
(I'm sorry but I think you made a mistake, PI is 3.14 not 3.15) :)
Simplify This.
15x+3-14x+4
Answers
Answer:
You just have to combine like terms to get the most simplified v erosion of this equation.
The final simplifed answer would be
x+7
Step-by-step explanation:
Well just add everything up.
15x-14x=x
3+4=7
Combine
x+7
Find sin(a) in the triangle.
Choose 1 answer:
Answers
Answer:
5/13
Step-by-step explanation:
Find the diagram to the question attached
Given the following considering angle A
Hypotenuse = 13 = AB
Opposite = 5 (side facing the angle A) = BC
Adjacent = 12
According to SOH CAH TOA;
Sin theta = opposite/hypotenuse
Sin(a) = BC/AB
Sin(a) = 5/13
Hence the value of sin(a) is 5/13
Min read 1/8 of his book before lunch and 1/4 of his book after lunch. He says he has read 2/12 of his book.
Which statement is most accurate?
Answers
Answer:
neither
Step-by-step explanation:
he has read 3/6 of his book