Question

The amount of a radioactive isotope decays in half every year. The amount of the isotope can be modeled by f(x) = 346(1/2)^x and f(1) = 173. What does the 1 represent?

A) The starting amount of the isotope
B) The amount of the isotope after one year
C) The rate the isotope decreases
D) The number of years that have passed

Answer 1

B. The number of years that have passed

Answer 2

Hello!

For the given equation, f(x) = 346(1/2)^x, every year, the radioactive isotope which is, 346, decreases in half, and in this function x represents each year. So if you were to substitute 1 into the function, you would get:

f(1) = 346(1/2)^1

f(1) = 346(1/2)

f(1) = 173

So therefore, the answer is B, the amount of the isotope after one year.