Answer: $1,203.49
Explanation:
The equal contributions will be an annuity. The $3,500 already there will also grow at 6% for 3 years. Expression is;
8,000 = ( 3,500 * ( 1 + 6%)^3) + Contribution * Future value interest factor of annuity, 3 years, 6%
8,000 = 4,168.56 + Contribution * 3.1836
Contribution = (8,000 - 4,168.56) / 3.1836
Contribution = $1,203.49