Question

A man gets ₹ 1,404 as interest at the end of one year. If the rate of interest is 12% per annum in R.D. account, the monthly instalment is ______.

विकल्प

• ₹ 1,200

• ₹ 1,800

• ₹ 2,400

• ₹ 3,600

Answer 1

A man gets ₹ 1,404 as interest at the end of one year. If the rate of interest is 12% per annum in R.D. account, the monthly instalment is ₹ 1,800.

Explanation:

Given as I = ₹ 1,404

n = 1 year = 12 month's,

R = 12%

Suppose P = ₹ x

`I = P xx (n(n + 1))/(2 xx 12) xx R/100`

= 1404

= ` x xx (12(12 + 1))/(2 xx 12) xx 12/100`

`\implies` 1404 = `x xx (12 xx 13)/(2 xx 12) xx 12/100`

`\implies` x = `1404 xx (2 xx 12)/(12 xx 13) xx 100/12`

x = ₹ 1800

∴ Monthly Instalment is ₹ 1800