If a 300g sample of a substance has a half-life of 5 days, how much of the substance will decay after 22 days?

A)293.4 g
B)290.6 g
C)285.8 g
D)299.9 g

5 answers

What is your answer?
Im not sure how to solve the question
First you need to know k in the formula
ln(No/N) = kt.
No = 300 g
N = what you solve for. This is what's left
k = 0.693/half life
t = time = 22 days
Then you want 300-N to give you what has decayed.
Post your work if you get stuck.
When I plugged in those numbers it ends up with 300/N=(0.693)(22) which gets me about 19.677. Then 300-19.677 gets me 280.323 and thats not an available answer.
My instructions were to post your work, not your answers with no work.