Answer:
60 compounding periods
Explanation:
The proper formula for compound interest is A = P(1 + r/n)^(nt), where r is the interest rate as a decimal fraction, n is the number of times that interest is compounded in 1 year, and t is the number of years.
In this problem, we don't need to calculate the Amount, but only the number of compounding periods. That is nt, which here is 12*5, or 60.