Question

The radioactive substance cesium-137 has a half-life of 30 years. The amount A (t) (in grams) of a sample of cesium-137 remaining after t years is given by the

following exponential function.
t
30
A (t) =621​

Answer 1

391, and 98

Explanation:

Plug in 20 where t appears:

621 (0.5)^20/30 = 621 x 0.62996 = 391.205

Rounded to 391

Plug in 80 where t appears:

621 (0.5)^80/30 = 621 x 0.6667 = 97.8

Rounded to 98