Question 772096
 b(t) = 1400e^0.25t,
At t = 0 the number of bacteria
will be = 1400
3 * 1400 = 4200
 b(t) = 1400e^0.25t,
4200 = 1400 e^0.25t
4200/1400 = e^0.25t
3 = e^0.25t
loge 3 = 0.25t loge e (loge e = 1)
t = loge 3/0.25
t = 4.39 hours
t = 4hrs 23mins.
Hope this helps.
:-)