An element with mass 730 grams decays by 27.6% per minute. How much of the element is remaining after 12 minutes, to the nearest 10th of a gram?

Answer 1

At the end of each minute, you have left (1.00 - 0.276) times what you had at the start of the minute.

1.00 - 0.276 = 0.724

The exponential decay law for this problem is

m(t) = 730 (0.724)^t,

where m(t) = remaining mass in grams t minutes after you started with 730 g.

Now plug in t=12 and finish from here.