2.5 hours = 5 x 30 minutes = 5 generations
5th generation = 32x10^6 => 2.5hrs
4th generation = 16x10^6 => 2hrs
3rd generation = 8x10^6 => 1.5hrs
2nd generation = 4x10^6 => 1hr
1st generation = 2x10^6 => 30mins
0 generation = 1x10^6 => 0mins
Therefore, the initial population is 1,000,000 bacteria
