If you retire at age 55, you work for 55 - 18 = 37 years. If you retire at 65, you work for 65 - 18 = 47 years.
OPTION 1: Age 55: (37 years)*($15,000 per year) = $555,000
Age 65 = (47 years)*($15,000 per year) = $705,000
OPTION 2: Use the compound interest formula, A = P(1 + r/n)nt
- A = the final amount
- P = the initial investment = $10,000
- r = the annual interest rate expressed as a decimal = 9.6% = 0.096
- n = the number of compoundings per year = monthly = 12
- t = years
Age 55:
A = $10,000*(1 + 0.096/12)12*37
A = $10,000*(1.008)444
A = $10,000*(34.4)
A = $344,000
Age 65:
A = $10,000*(1 + 0.096/12)12*47
A = $10,000*(1.008)564
A = $10,000*(89.5)
A = $895,000
A = $10,000*(1.008)564
A = $10,000*(89.5)
A = $895,000
Which option would you pick at age 55? at age 65?