Okay I don't understand any of this & if I could get someones help I would appreciate it so much. We learned before the compounding formulas. I thin some how they relate but I don't know. Please help.

Problem:

At the beginning of an experiment, a scientist has 216 grams of radioactive goo. After 225 minutes, her sample has decayed to 27 grams.

What is the half-life of the goo in minutes?

Find a formula for

, the amount of goo remaining at time

.

How many grams of goo will remain after 8 minutes?

Hint: do part 2 first, i.e. you are just finding k from given pair. Then to find half-life, set outcome G(t) to be 1/2 of starting amount and solve for t.