Answer:
$4500
Explanation:
Simple Interest formula = Principal × Rate × Time
Let the amount of the money invested at 8% Interest = x
Hence:
$5000 × 6% × 1 + x × 8% × 1 = $660
$300 + 0.08x = $660
0.08x = $660 - $300
0.08x = $360
x = $360/0.08
x = $4500
Therefore , the amount that must be invested at 8% interest is $4500