Given:
The rate of interest is, r = 7.5% = 0.075.
The required total amount is, A = $15,000.
The number of years, t = 6 years.
The objective is to find the principal amount required to invest.
Step-by-step explanation:
The general formula of compound interest is,

Here, n represents the number of times the interest is compounded.
It is given that the interest is compounded monthly, so the value of n = 12.
To find principal amount:
Substitute the given values in the above formula.

To find APY:
The annual principal yield can be calculated as,

To find percent change:
The percent change can be calculated as,

Hence,
The principal money to be invested in the account is $ 9577.83.
The Annual Percent Yield is 0.0776.
The percent change for 6 year is 56.6%.