Originally Posted by

**mvho** Please let me know if I am on the right track or way off tangent!

**Plutonium 241: A(t)=Aoe^-.053t**

Q: The Half Life of Plutonium 241 is approximately 13 years.

A: How much of a sample weighing 4g will remain after 100 years?

B: How much time is necessary for a sample weighing 4g to decay to .1g?

So for question A, this is what I thought:

1/2=4e^-.053 (100)

On the left hand side, I used 1/2 to represent the half life and on the RS, I plugged in 4 for Ao which is my initial amount? For T, I used 100 years for time. This is where I think I goofed up. I don't think I set up the equation correctly.

TIA