ok in my professors notes he calculates carbon 14 age in an example.

Question

The problem goes like this:
Sample contains 110g carbon
sample produces 70 disintegrations per minute.
That is 0.7 disintegrations per minute.
T=(1/lambda)ln(N0/Nt)

Then he substitutes:
t=(1/1.209*10^-4/year)ln(1600/70)

I just want to know where did he get 1600 from?

Answer 1

No is 1600 disintegrations per minute, it was the disintegrations per minute in the original sample at the beginning.

What concerns me is the last two lines of your text notes..
sample produces 70 disintegrations per minute, that is .7 diintegrations per minute. Huh?

Answer 2

I wrote exactly what he had in his notes. so what should the actual t=? is everything else correct except the 1600? I have no examples in my book.