# This is a multiple choice question. A certain radioactive substance is decaying so that at time t, measured in years, the amount of the substance, in grams, is given by the function f(t)=-e^t +10. what is the rate of decay of the substance after 1 year?

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the choice are

a) -3 g/year

b) -ln 2 g/year

c) -2.72 g/year

d)-1.53 g/year

the choice are

a) -3 g/year

b) -ln 2 g/year

c) -2.72 g/year

d)-1.53 g/year

##### 1 Answer

Apr 21, 2018

C.

#### Explanation:

If the amount of substance left is given by

So, find the first derivative, recalling that the derivative of the natural exponential function

To determine the rate of decay after

The correct answer is C.