Question

if 15/16 of 12 atom an element decay in 8minutes. find the decay constant of the element.

Answer 1

if 15/16 of 12 atom an element decay in 8minutes
HUH?

All I can do is guess that 1/16 of the original amount remains after 8 minutes
if a = A e^-kt
1/16 = e^-8k
ln (1/16) = - 8k
-2.77 = -8k
k = 0.347 /min