Question

PLEASE HELP ASAP! Billy is monitoring the exponential decay of a radioactive compound. He has a sample of the compound in a test tube in his lab. According to his calculations, the sample is decaying at a rate of 35% per hour. There are at least 72 grams of the sample remaining. Once the sample reaches a mass of 15 grams, Billy will continually add more of the compound to keep the sample size at a minimum of 15 grams.

If R represents the actual amount of the sample remaining, in grams, and t represents the time in hours, then which of the following systems of inequalities can be used to determine the possible mass of the radioactive sample over time?

Answer 1

the answer to the question is b

Answer 2

The correct option is B.

Explanation:

Consider the provided information.

Billy is monitoring the exponential decay of a radioactive compound.

As it is given that, the sample is decaying at a rate of 35% per hour.

So, 35% can be written as:

`(35)/(100)=0.35`

Note: If the exponent of "e" is a positive number, then the sample will increase, but it is given that Billy is watching a radioactive decay. Therefore the exponent of "e" must be a negative number.

Thus, the exponent of "e" should be -0.35t.

Now, observe the provided options, only option B has
`e^(-0.35t)`.

Therefore, the correct option is B.