How much money I had put on interest?

Question

I had kept some money was put on simple interest for 2 years, had it been put on 3% more interest then I would have fetched $72 more. How much money I had put on interest?

Answer 1

$1200.00

Let the sum invested be a
If a had been invested at 3% more interest then it would have earned $72.00 more for 2years.

So, the 3% of the amount a invested for 2 yrs = $72.00, so interest for 1yr = $36.00

Now,

a * 3% = $36.00
so, a = $36.00/3%
thus,

a = $1200.00

Thus, the money put on interest is $1200.00