The nuclide 96Nb decays by a first-order process with a rate constant of 2.96 × 10-2 h-1. How long will it take for 85% of the initial amount of 96Nb to be consumed?

Question

I believe it is 5.07 hrs...

Answer 1

nope.
ln(No/N) = kt
No = 100 (You can choose any convenient number)
N = 15 (85% has been consumed)
k = 0.0296