Culture B doubles every 3.00 days, therefore:

*l*n 2 = 3 k_{B}

k_{B} = 0.231 day^{-1}

Now we have for any time t:

N_{A} = 1000e^{0.05t} and N_{B} = 1500e^{0.231t}

The question asks: How long until culture B has p
times as many cells as culture A?

This means: