One of the main contaminants of a nuclear accident, such as that at chernobyl, is strontium-90, which decays exponentially at a rate of approximately 2.5% per year.

(a) write the ratio of strontium-90 remaining, p , as a function of years, t , since the nuclear accident.

Step-by-step explanation:

We know that the general form of the exponential decay formula is

, where y is final amount remaining after t time, A is the original amount and r is the rate of decay

Now, the ratio of strontium-90 remaining, p , as a function of years, t , since the nuclear accident.

Hence, the ratio of remaining since the nuclear accident is

the answer is d. 75%

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50