Given initial savings are 15,000 dollars.
It says to place one-third in an account with 4.6% APR compounded annually. So we invest $5,000 in this account.
Amount after 3 years = 15000(1+0.046)³ = 17,166.68 dollars.
Remaining Balance = 15,000 - 5,000 = 10,000 dollars.
It says to place one-quarter of the remaining balance into 3-year bond with 5.2% APR compounded annually. So we invest $2,500 in this bond.
Bond's value after 3 years = 2500(1+0.052)³ = 2,910.63 dollars.
Remaining Balance = 10,000 - 2,500 = 7,500 dollars.
It says to invest rest in a stock that increases in value 3% the first year; decrease 8% in value the second year; and increases 6% in value in the third year.
Stock's value after 3 years = 7500×(103%)×(92%)×(106%) = 7500 x 1.03 x 0.92 x 1.06 = 7,533.42 dollars.
Total amount after 3 years = Saving Account + Bond value + Stock value = 17,166.68 + 2,910.63 + 7,533.42 = 27,610.73 dollars.
Total Gain in the original savings = 27,610.73 - 15,000 = 12,610.73 dollars