Question

A sum of 1550 was lent partly at 8 % simple interest. The total interest received after 3 years is rupees 300. What is the ratio of the money lent at 5 % to that lent at 8 %.

Answer 1

Let the sum lent at 5% be Rs.x and that lent at 8% be Rs.(1550-x).

Then,  

Interest on x at 5% for 3 years + interest on (1550 - x) at 8% for 3 years = 300

 $= \frac{ x\times 5\times3}{100}$  $+ \frac{ (1500 - x)\times 8\times3}{100} = 300$

x = 800

Ratio =  x : (1550-x)

         = 800 : (1550-800)

         = 800 : 750

          = 16 : 15

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