An investment yielded an interest payment

An investment yielded an interest payment of $350 each month when the annual interest rate was 9%, what is the amount of the investment that should be invested with an annual interest rate of 8% if We want to gain 15% more each month?

(a) $60,375
(b) $50,400
(c) $41,300
(d) $32,500
(e) $25,100

The best answer is A.
The new monthly payment should be 1.15 x $350 = $402.5. Now we’ll proceed with the formula:

Principal × percent interest = interest earned

Principle×  (0.08)× 1/12 = $402.5.

Solve for the principal (402.5 × 12)/.08= $60,375.