Question

Sheba opened a retirement account with $36,500. Her account grew
at a rate of 7% per year compounded annually. She made no deposits
or withdrawals on the account. At the end of 20 years, what was the
account worth, to the nearest dollar?
(1) $87,600 (3) $141,243
(2) $130,786 (4) $1,483,444,463

Answer 1

After 20 years, the account is worth 3) $141,243 rounded to the nearest dollar.

7% interest rate compounded annually means that the interest earned also earns an interest  with the rate of 7%. Thus, the principal is multiplied with 1.07 or 107%.

Y1        36,500.00                         1.07      39,055.00     
Y2        39,055.00                         1.07      41,788.85     
Y3        41,788.85                         1.07      44,714.07     
Y4        44,714.07                         1.07      47,844.05     
Y5        47,844.05                         1.07      51,193.14     
Y6        51,193.14                         1.07      54,776.66     
Y7        54,776.66                         1.07      58,611.02     
Y8        58,611.02                         1.07      62,713.80     
Y9        62,713.80                         1.07      67,103.76     
Y10      67,103.76                         1.07      71,801.02     
Y11      71,801.02                         1.07      76,827.10     
Y12      76,827.10                         1.07      82,204.99     
Y13      82,204.99                         1.07      87,959.34     
Y14      87,959.34                         1.07      94,116.50     
Y15      94,116.50                         1.07    100,704.65   
Y16    100,704.65                         1.07    107,753.98   
Y17    107,753.98                         1.07    115,296.76   
Y18    115,296.76                         1.07    123,367.53   
Y19    123,367.53                         1.07    132,003.26   
Y20    132,003.26                         1.07    141,243.48