The half-life of radium is 1690 years. If 80 grams are present now, how much will be present in 870 years?
grams

Answers

Answer 1

Answer:

A(t) = amount remaining in t years

= A0ekt, where A0 is the initial amount and k is a constant to be determined.

Since A(1690) = (1/2)A0 and A0 = 80,

we have 40 = 80e1690k

1/2 = e1690k

ln(1/2) = 1690k

k = -0.0004

So, A(t) = 80e-0.0004t

Therefore, A(430) = 80e-0.0004(430)

= 80e-0.172

≈ 67.4 g

Step-by-step explanation:

hope it helpful for you ❤️


Related Questions

f(x-1)=3x²-7x+8, find f(x)​

Answers

Answer:

  f(x) = 3x² -x +4

Step-by-step explanation:

Use (x+1) for x and simplify.

  f((x+1) -1) = 3(x +1)² -7(x +1) +8

  f(x) = 3(x² +2x +1) -7x -7 +8

  f(x) = 3x² -x +4

in a supermarket, credit card purchases have an additional charge of 8% of the purchase made. If I bought 2 suitcases that cost s / .165.60 each and paid with a credit card, how much do I have to pay?

Answers

9514 1404 393

Answer:

  357.70

Step-by-step explanation:

The final cost will be ...

  (number of suitcases) × (cost per suitcase) × (1 +8%)

  = 2(165.60)(1.08) = 357.70

HELP FAST, I'LL GIVE BRAINLIEST, 50 POINTS!!!
-2.25+0.4x=-2.8
Solve and show your steps in both fraction form, and decimal form

Answers

Answer:

Decimal = -1.375, Fraction = -11/8

Step-by-step explanation:

Decimal:

-2.25 + 0.4x = -2.8

0.4x = -0.55

x = -1.375

Fraction:

-9/4 + 2/5x = -14/5

-45/20 + 8/20x = -56/20

8/20x = -11/20

x = -11/8

Hopefully this helps!

Brainliest please?

The sixth number 20210A is prime for only one digit A. What is A?

Answers

9514 1404 393

Answer:

  A = 9

Step-by-step explanation:

Beyond the first few primes, all prime numbers end in one of the odd digits, 1, 3, 7, or 9. We can reduce this list by using a couple of simple divisibility rules.

The sum of the digits is 2+0+2+1+0+A = A+5. The number will be divisible by 3 if A+5 is divisible by 3. That will be the case for A=1 and A=7.

The sum of odd digits is A+1+0 = A+1. The sum of even digits is 0+2+2 = 4. When these sums are equal, the number is divisible by 11. That will be the case for A=3.

So, we have ruled out all digits except 9. If the number is prime it must be ...

  202109

  A = 9

_____

Additional comment

To make sure the number is prime, we would need to check divisibility by all primes less than √202109 ≈ 449.

Answer: 9

the answer is 9 because if i root 202109 i get about 446 and if its decimal it prime

A farm lets you pick 3 pints of raspberries for $12.00. How many pints do you get per dollar?

Answers

Answer:

it would take 4 dollars to get one pint. if that's what your asking.

Step-by-step explanation:

divide 12 by 3 or multiply 3 by 4 which gives you 12. your answer is 4 if i understand correctly.

Circle the multiplication problem that does not belong with the other three. explain 12×8=,22×4=,42×2=,33×3=

Answers

Answer: 12 x 8

Step-by-step explanation: The other three are not the basic multiplication facts from 0 - 12.

What is 26 out of 100 expressed as a ratio in simplified form?

Answers

26:100

..............................

26 percent in simplest form is the fraction 13/50. Since 'percent' means 'per hundred,' 26 percent would be equivalent to the fraction 26/100.

Estimate 5,924 ÷ 33 =
please this is all I ask is what is this?
I need it ASP

Answers

Answer:

179.6 (Estimated)

Step-by-step explanation:

5,924 ÷ 33 = 179.6 (Estimated)

Hoped this helped.

Answer:

5,924 ÷ 33 = 179.6 (in estimated form)

Step-by-step explanation:

5,924 divided by 33 equals 179.515151515.

Since 179.515151515 is not in estimated form, this can't be the correct answer.

Since we see that 51 is repeating, this allows us to determine whether we can round this up or not.. And we can!

179.515151515 → 179.6

Since 51 was repeating, we could round it up.

Therefore, 179.6 is your final answer.

Hope this helps! :D

(Can you mark me brainliest? It is greatly appreciated!)

- ♥ 7272033Alt ♥

I’ll mark you brainliest if you help me answer 1-9 (no bs)

Answers

yyyy yy yy yuy idont know

Answer:

1. 0

2. undefined

3. 0

4. 0

5. undefined

6. undefined

7. undefined

8. 0

9. 0

Step-by-step explanation:

25 + -100 = 25 - n solve the equation mentally

Answers

Answer:

n = 100

Step-by-step explanation:

25 + -100 = 25 - n

=> -100 = -n

=> n = 100

Hoped this helped.

[tex]25-100 = 25 -n\\\\\implies -100 = -n\\\\\implies n = 100[/tex]

You are playing a game where you draw a card from a standard deck, and you will win $13 if you draw a face card,
$3 if you draw an ace and lose $5 if you draw any other card. What is the expected gain from this game?

Round your final answer to the nearest cent.

Answers

Answer:

Step-by-step explanation:

win

There are 3 face cards / suit. Every suit contains a Jack, Queen, and king.

There are 4 suits so the number of face cards is 3*4 =  12

There is 1 ace / suit

There are 4 suits so the number of aces is 1 * 4 = 4

The gain from the face cards = 12 * 13 = 156

The gain from the aces = 4 * 3 =               12

Total gain = 168

Losses

Any other card costs you $5

How many cards is that? 52 - 16 = 36

Each one costs 5 dollars

Total loss = 5 * 36 = 180

So each time you play the game, you can expect to lose 180 - 68 = 12 dollars. You should walk away quickly from this one.

Roger’s office building has a $320,000 value, a 2 rating, and a B building classification. The contents in the building are valued at $105,000. Calculate his total annual premium.

Answers

Answer:

2,230

Step-by-step explanation:

On the unit circle, where 0 less-than pi, when is tangent theta undefined?
Theta = pi and Theta = 2 pi
sine theta = cosine theta
Pi = StartFraction pi Over 2 EndFraction and Pi = StartFraction 3 pi Over 2 EndFraction
sin theta = StartFraction 1 Over cosine theta EndFraction

Answers

Answer:

Option 3

Step-by-step explanation:

As tanθ = sinθ/cosθ, tanθ will have a problem when cosθ goes to zero.

cosθ is at 0 when θ = π/2 and at 3π/2

Answer:

c

Step-by-step explanation:

c

It takes 6 fruit pickers 18 hours to pick a field of fruit. How long would it take 8 fruit pickers to pick the same field.​

Answers

So I believe it is 13.5 hours because you need to multiply 6 and 18, and the total of that should be divided by 8

Time taken by [tex]8[/tex] fruit pickers to pick the fruits of the same field is equals to [tex]13.5[/tex]hours.

What is time?

" Time is defined as the continues process which help us to measure the period/ length of occurring of event. It does not have any dimensions."

According to the question,

Time take by [tex]6[/tex] fruit pickers to pick the fruit from the field [tex]= 18[/tex]hours

As per the given situation we have,

Time taken by[tex]8[/tex] fruit pickers to pick the fruits of the same field

[tex]=\frac{(6)(18)}{8}[/tex]

[tex]=13.5[/tex]hours

Hence, time taken by [tex]8[/tex] fruit pickers to pick the fruits of the same field is equals to [tex]13.5[/tex]hours.

Learn more about time here

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Five more than the difference of two numbers

Answers

Answer: (x - y) + 5

Step-by-step explanation: Difference of two numbers means subtraction so we know its x - y. Then, we need five more so addition which means (x - y) + 5.

Would appreciate brainly <3

3^9 times 3^7 in exponential form

Answers

Answer:

3¹⁶

Step-by-step explanation:

While adding numbers with exponents, if the base of the numbers is same, then it will also be the same in the final answer and the exponents add

Hope this helps!

Answer:

You can just add the exponents power

9+7=16

So its 3^16 in exponential form

You can think of it like this.

for 3^9 its

3*3*3*3*3*3*3*3*3

And for 3^7 its

3*3*3*3*3*3*3

Now your multiplying them all together.

Really your jsut adding the value so in the end

3*3*3*3*3*3*3*3*3*3*3*3*3*3*3*3

So its

3^16

guys please help this is graded
For the number line shown, which statement is not true?

Answers

Answer:

The first one is incorrect

Step-by-step explanation:

|a| would still be less than b, because you are mirroring a on the other side of b.

The diagram shows where |a| would lie.

-Chetan K

It’s the first choice! Hope this helps

help me please i beg you

Answers

ANSWER: Acute and obtuse angle

Estimate the product.
627x 3.73

Answers

2,520

Estimate 627 to 630

3.73's closest estimate is 4

So, 630*4=2,520

Can some help please

Answers

Answer:

9×10^16

Step-by-step explanation:

Only if the power is the same, you can just add the first numbers

You just need to combine.

The rule (a) = a tells us we can just remove the parenthesis.

2*10^16 + 7*10^16

That would equal to 9 x 10^16 because when adding exponents, you keep them the same.


A collection of 77 quarters and dimes is worth $12.50. How many quarters are in the collection? PLS HELP ILL GIVE YOU BRAINLEST ANSWER

Answers

Answer:

32

Step-by-step explanation:

77 quarters and dimes

q + d = 77

subtract q from both sides

d = 77 - q

---------------------------

A collection of  quarters and dimes is worth $12.50 (1250 cents)

25q + 10d = 1250

substitute for d

25q + 10(77 - q) = 1250

distribute

25q + 770 - 10q = 1250

Combine like terms

15q + 770 = 1250

subtract 770 from both sides

15q = 480

divide both sides by 15

q = 32

okay this is what i need help with its kinda easy

Answers

Answer:

B is the answer .......+4+$#88#!$

Are the two ratios that make up a proportion
always, sometimes, or never equivalent

Answers

Answer:

Always

Step-by-step explanation:

In mathematics, when we say that two ratios form a proportion, we mean that the two ratios are equal.

Ex: Ratios and Proportions - Proportions - In Depth. A proportion is simply a statement that two ratios are equal. It can be written in two ways: as two equal fractions a/b = c/d; or using a colon, a:b = c:d. The following proportion is read as "twenty is to twenty-five as four is to five."

A proportion is two ratios which have been set equal to each other; a proportion is an equation that can be solved. When I say that a proportion is two ratios that are equal to each other, I mean this in the sense of two fractions being equal to each other. For instance, 105 equals 21 .

The two ratios sometimes that make up a proportion.

What is Proportional?

Any relationship that is always in the same ratio and quantity which vary directly with each other is called the proportional.

We know that;

Two ratios that make up a proportion when both ratios are equal to each other.

And, When two ratios are not equal then it cannot make a proportion.

Hence, The two ratios sometimes that make up a proportion.

Learn more about the proportion visit:

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If f(x) = 4x + 3x2 + 1, then what is the remainder when f(x)
is divided by X -2?

Answers

Answer:

remainder = 21

Step-by-step explanation:

If f(x) is divided by (x - h) then the remainder is f(h)

Here f(x) is divided by (x - 2) with h = 2 , then remainder is

f(2) = 4(2) + 3(2)² + 1 = 8 + 3(4) + 1 = 8 + 12 + 1 = 21

At the math store each circle costs one amount and square cost anthor. 5 circles +1 square =20 cents, two circles +3 square=21 cents . At these prices how many cents does 12 circles + 5 squares cost?

Answers

Answer:

61 cents

Step-by-step explanation:

We can create 2 equations.

5C + (1)S = 20

2C+ 3S = 21

We can alter the first equation below

S = 20 - 5C

Now we replace S with 20 - 5C into the second equation as shown

2C + 3(20 - 5C) = 21

Simplify:

2C + 60 - 15C = 21

Combine Like Terms:

-13C = -39

C = 3

Now we can calculate S

S = 20 - 5(3)

S = 5

12(3) + 5(5) = 36+25 = 61

Hey I just wanted to know if anyone could help me out with this, I really would love the help.

Thank you :)

Answers

Answer:

3x-6   A.

Step-by-step explanation:

I would glady help anyone.

You welcome.

Harley has 60 beads. There are 11 beads that are NOT round. The rest are round. How many round beads does Michelle have?
Help please

Answers

Answer:

49

Step-by-step explanation:

If there's 60 beads in total and 11 are round and the rest aren't all you have to do is subtract 11 from 60.

Like This: 60-11=49

To check your answer you can add them to see if you get 60. Like this: 11+49=60

Suppose y = sqrt 2x+1, where x and y are functions of t.
(a) If dx/dt = 9, find dy/dt when x = 4.
(b) If dy/dt = 3, find dx/dt when x = 40.

Answers

If y = √(2x + 1), then differentiating both sides implicitly with respect to t gives

dy/dt = 1/2 • 1/√(2x + 1) • 2 • dx/dt = 1/√(2x + 1) • dx/dt

(a) If dx/dt = 9 and x = 4, then

dy/dt = 1/√(2•4 + 1) • 9

dy/dt = 1/√(8 + 1) • 9

dy/dt = 1/√9 • 9

dy/dt = 9/3

dy/dt = 3

(b) If dy/dt = 3 and x = 40, then

3 = 1/√(2•40 + 1) • dx/dt

3 = 1/√(80 + 1) • dx/dt

3 = 1/√81 • dx/dt

3 = 1/9 • dx/dt

dx/dt = 27

It took the Selby family hours round -trip to drive from their house to their beach house 154 miles away . Find their average speed . 5 1/2

Answers

Step-by-step explanation:

Distance = 154 miles .

Time = 5 ½ hrs .

We know ,

Speed = s / t

v = 154 mi/ 5.5 hrs = 28 mi / hr

One year, professional sports players salaries averaged $1.6 million with a standard deviation of $0.9 million. Suppose a sample of 400 major league players was taken. Find the approximate probability that the average salary of the 400 players exceeded $1.1 million.​

Answers

Answer:

1

Step-by-step explanation:

One year, the distribution of salaries for professional sports players had mean $1.6 million and standard deviation $0.8 million. Suppose a sample of 400 major league players was taken. Find the approximate probability that the average salary of the 400 players that year exceeded $1.1 million.

z = (x-μ)/σ/√n

where

x is the raw score

μ is the population mean

σ is the population standard deviation

n = random number of samples

Mean $1.6 million and Standard deviation $0.8 million.

z = (1100000- 1600000)/800000/√400

z = -500000/800000/20

z = -500000/40000

z = -12.5

Probability value from z score table is :

P(x ≤ Z) = P(x = 1100000) = P(z = 12.5)

= 0

P(x>Z) = 1 - P(x < Z)

= 1 - 0

= 1

The approximate probability that the average salary of the 400 players that year exceeded $1.1 million is 1

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