Question

If ₹ 3,750 amount to ₹ 4,620 in 3 years at simple interest. Find:
(i) the rate of interest
(ii) the amount of Rs. 7,500 in `5 1/2` years at the same rate of interest

Answer 1

(i) A = Rs.4620 

P = Rs.3750

I = A − P = Rs.4620 − Rs.3750 = Rs.870

T = 3 years

`"R"=(100xx"I")/("P"xx"T")=(100xx870)/(3750xx3)=(100xx290)/3750=(4xx29)/15`

`=116/15=7 11/15%`

(ii) P = Rs.7500

R = `116/15%`

T =`5 1/2` years = `11/2` years

Interest =`("P"xx"T"xx"R")/100`

= Rs.`(7500xx11xx116)/(2xx15xx100)=(250xx116xx11)/ 100`

= 10 × 29 × 11 = 290 × 11 = Rs.3190

Amount = Rs.7500 + 3190 = Rs.10,690