Answer:
$4,208.5
Explanation:
The simple interest rate of the college savings account, R = 5.5%
The amount with which the account was opened, P = $500
The amount added each month to her account = $50
The amount in her account after 4 years = Required
The interest on each added $50 is given as follows;
50 × 0.055/12 × (1 + 2 + 3 + ... + 47) = 50 × 0.055/12 × (47/2)(1 + 47) = 258.5
The total amount deposited = 500 + 50 × 47 = $2,850
The total interest = 500×0.55×4 + 50 × 0.055/12 × (47/2)(1 + 47) = 1,358.5
The amount in her account at the end of 4 years, A, is given as follows
A = $2,850 + $1,358.5 = $4,208.5