A man invested an amount at 10% per annum and another amount at 8% per annum simple interest. Thus, he received ₹ 1350 as annul interest. Had he interchanged the amounts invested, he would have received ₹ 45 less as interest. What amounts did he invest at different rates ?

Answer

₹ 8500 at 10 % p.a and ₹ 6250 at 8% p.a.

Explanation

Suppose he invested ₹ x at 10 % p.a. and ₹ y at 8 % p.a.
`((x xx 10 xx 1))/(100) + (( y xx 8 xx 1))/(100) = 1350 rArr 5x + 4y = 67500" " `… (i)
`((x xx 8 xx 1 ))/(100)+ (( y xx 10 xx 1 ))/( 100) = 1350 - 45 rArr 4x + 5y = 65250 " "`... (ii)
Add (i) and (ii). Then, subtract (ii) from (i).