Exponential and Logarithmic Models

Question

At the beginning of an experiment, a scientist has 252 grams of radioactive goo. After 165 minutes, her sample decayed to 3.9375 grams.

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

Find a formula for G(t), the amount of goo remaining at time t

G(t)=G(t)=   

How many grams of goo will remain after 62 minutes?   

You may enter the exact value or round to 2 decimal places.

Answer 1

3.9375 = 225e^165k

0.0175 = e^165k

ln 0.0175 = 165k

Solve for k.

Then use that value in

0.5 = e^kt

And solve for t.