A person invests $1500 annually to accumulate at 12%p.a. What will the credit balance of this investment be after making the 16th payment?

1500(1.12+1.12^2…1.12^16)

Credit Balance: [1.12(1.12^16 – 1)]/(1.12 – 1)

But I get $71826, while the answer is $64130

Also,

In the first year of joining a superannuation fund a woman invests $400. The interest rate is 12% p.a. Each year the woman invests an additional 10% of the amount invested in the previous year to allow for inflation. How much does she invest in the second year? How much does she receive after 20 years?

Thank you for any help given