If a particular type of cell completes one cell cycle in 75 minutes and you start with one cell how many cells would be present after 7.5 hours

Solution:

7.5 hours x 60 minutes = 450 minutes 
450 minutes / 75 minutes = 6 total cycles 

It starts with 1 cell then splits into 2, then two split into 4, then again to 8, then plits again to 16, then again 32, then splits again to 64. Think of that every new cell will also split into two cells, not just the one you go in full swing with. 

A faster way to compute is 2^6 = 64. So therefore, 1-2-4-8-16-32-64

an economic reason that the south needed a reconstruction plan is that plantations, factories, and other businesses were destroyed during the war.