This rich aunt invests $37000 in a savings bond for the baby which earns 1.125% interest every quarter. How much total interest has this savings bond earned 24 quarters after the rich aunt invested

Question

I've been struggling to figure this out, I've tried compounding this semi-annually but somehow its still incorrect

Answer 1

If the interest is simple interest (based on quarters) the interest over 24 quarters (6 years)=

37000×24×1.125/100=$9,990.

If it's compound interest (compounded quarterly) the growth rate of the investment=1.01125²⁴=1.308 approx. So $37000 grows to $48395.68. The interest is therefore 48395.68-37000=$11,395.68, which is $1,405.68 more than the simple interest.