* P = principal amount (initial investment)
* r = annual nominal interest rate (as a decimal)
* n = number of times the interest is compounded per year
* t = number of years
* A = amount after time t
In your case
P = 1500
r = 0.045
n = 12 (there are 12 months in a year)
A = 2P
t = t
Part A is asking for what value of t does . Sub in your values and find t.
Continuously compounded interest means we can use in part B and the formula becomes . In this case you are solving for n.