Question

A sum of 2100 is lent out in two parts. If the interest on one part at 9% p.a. for 5 years is equal to the interest on the other part at 25/4% p.a. for 4 years, find the part lent out at 9% p.a.?

Answer 1

Let x rupees be put at 9% p.a. for 5 years,than interest

$\frac{x \times 9 \times 5}{100} \\ \\ = \frac{9x}{20}$
Amount left with (2100-x) Rs be put at 25/4% p.a. for 4 years

$\frac{(2100 - x) \times 25 \times 4}{4 \times 100} \\ \\ = \frac{(2100 - x)}{4}$
Since both the interest are equal,so equate these two interest calculated above

$\frac{9x}{20} = \frac{2100 - x}{4} \\ \\ \frac{9x}{5} = 2100 - x \\ \\ 9x = 5(2100 - x) \\ \\ 9x =10500 - 5x \\ \\ 9x + 5x = 10500 \\ \\ 14x = 10500 \\ \\ x = \frac{10500}{14} \\ \\ x = 750$
So the money lend at 9% p.a is 750/- Rs.

Hope it helps you.

Answer 2

Answer:

Hope this will help !!