Given the following data for a post -retirement contribution

Annual contribution : 7500

tax bracket: 15%,

Effective rate: 9% ,

Investment years: 25

Note specific instructions: Calculate the available retirement income (after tax) by: 1)reducing the contribution amount by the tax you would have to pay on that amount BEFORE calculating the final annuity amount.

So: After reducing the contribution amount by the tax you would have to pay on that amount then

Calculate the interest earned and

Calculate balance after taxes

(I got $420,089.9741 as the available retirement income.. is this correct?)

NOTE: the answer is not $539,968.21.