Answer: $34,502.85
Explanation:
The constant deposits are considered annuities.
The value at the end of 22 years is the future value of the annuity.
Future value of annuity = Annuity * ( (1 + rate)^number of years - 1 ) / rate
= 1,000 * ( ( 1 + 5%) ²² - 1) / 5%
= $38,505.21
Then subtract the future values of the deposits that your grandmother missed.
For the fifth birthday, the future value term will be 22 - 5 = 17 years
For the eleventh, the future value term will be 22 - 11 = 11 years
The amount in the account is:
= 38,505.21 - (1,000 * 1.05¹⁷) + (1,000 * 1.05¹¹)
= $34,502.85