A.)
Think of this problem as an interest problem. After a certain amount of time, your money (cells) will double.
The standard equation for simple compounding interest is y = P(R)^x
where
P is the principal/ initial amount
R is the rate at which your principle will increase
x is the time interval (seconds, days, year, etc.)
y is the final amount after x time
Knowing that we can make an equation
N= 1000(2)^(h)
where h is (t/14)
t is in hours so every fourteen hours the expression h increases by 1 and so the equation N doubles.
B.)
There are 24 hours in a day so in 2 days that is 48 hours
h will then be 48/14
plug this into the equation and you get
N= 1000(2)^(48/14) = 10767 cells (rounding down because you can't have a portion of a cell)