Question

The cells of a certain culture of bacteria triple every 2 minutes. If there are 40 cells in the beginning, in how many minutes will there be more than 9500 cells?
A) 4 min
B) 5 min
C) 11 min
D) 10 min

Answer 1

9500=40×(3)^t
Where t is the number of minutes
Solve for t
9500/40=3^t
Take the log
Log (9500/40)=log (3)×t
Divide each side by log (3)
T=log(9,500÷40)÷log(3)
T=4.9 minutes

So there will be more than 9500 cells in 5 minutes