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serious [3.7K]
3 years ago
7

Colbalt-60 has half-life of about 5 years, How many grams of a 300 g sample will remain after 20 years?

Mathematics
2 answers:
ZanzabumX [31]3 years ago
5 0

Answer:

After 20 years 18.75 gm of sample will remain.

Step-by-step explanation:

Rashid [163]3 years ago
4 0

The half-life is the time it takes for any amount of Cobalt-60 to decay to half the starting amount.

20 years is 4 times the half-life of 5 years. So there would be

(300 g) / 2⁴ = 18.75 g

remaining after 20 years.

In other words, after 5 years, 300 g decays to 150 g.

After another 5 years (total 10 years), 150 g decays to 75 g.

After another 5 years (total 15 years), 75 g decays to 37.5 g.

After another 5 years (total 20 years), 37.5 g decays to 18.75 g.

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allsm [11]

Answer:

Step-by-step explanation:

P(a or b) = P(a) + P(b) - P(a and b)

0.88 = 0.70 + 0.60 -  P(a and b)

P(a and b) = 1.30 - 0.88 = 0.42.

So the events a and b are not mutually exclusive.

4 0
2 years ago
On a unit circle, the vertical distance from the x-axis to a point on the perimeter of the circle is twice the horizontal distan
swat32

Check the picture below.

since the vertical distance, namely the y-coordinate, is twice as much as the horizontal, then if the horizontal is "x", the vertical one must be 2x.

let's find the hypotenuse first.

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5 0
3 years ago
The qestion is the picture ​
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Answer:

-2/9

Step-by-step explanation:

3 0
3 years ago
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Mara found the length of time of an investment. The principal of the investment was $4,300, the interest rate was 6.2 percent, a
Ivanshal [37]

The error that Maria made is that she did not divide correctly.

<h3>What error did Maria make?
</h3>

The simple interest that is paid on an amount of money is a function of the amount deposited, time and interest rate.

Simple interest = principal x time x interest rate

2666 = 4300 x 0.062 x t

2666 = 266.60t

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To learn more about simple interest, please check: brainly.com/question/27328409

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2 years ago
Is -2/9 greater or less then -4/9
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