Question

: On what sum of money lent at 9% per annum for 6 yrs. does the S. I. amount to
Rs. 810 ?
(1) 1000 Rs.
(2) 1500 Rs.
(3) 1200 Rs
(4) 1600 Rs.​

Answer 1

Answer:

A certain sum of money amounts to Rs. 1250 at simple interest in 3 years and Rs. 1500 in 4 years. What is the sum and rate of interest?

Let x be the sum of money and y be the rate of Interest

Using formula for Simple Interest, we have,

x + x * 3 * y / 100 = 1250

i.e. x + 0.03xy = 1250 — (i)

Also, we have,

x + x * 4 * y / 100 = 1500

i.e. x + 0.04xy = 1500 — (ii)

Subtracting, equation (i) from (ii), we get,

0.01xy = 250

i.e. xy = 25000 — (iii)

Substituting equation (iii) in (i), we get,

x + 0.03 * 25000 = 1250

i.e. x + 750 = 1250

i.e. x = 500 — (iv)

Substituting equation (iv) in (iii), we get,

500y = 25000

y = 50

So, the sum is Rs. 500/- and rate of Interest is 50% p.a.

Step-by-step explanation:

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