31.9% = 0.319, so all you have to do is solve the equation 120,493 - (120,493 * 0.319^n), where n stands for the number of years. So...

120,493 - (120,493 * 0.319^4) = 119245.26 , so $119245.26 on the 4th year

120,493 - (120,493 * 0.319^9) = 120488.88 , so $120488.88 on the 9th year

(The answers where rounded to the nearest hundreth)