A man invests a total sum of Rs. 10,000 in a company. A part of the sum was invested at 10% simple interest per annum and the remaining part at 15% simple interest per annum. If the total interest accrued to him in two years equals Rs. 2,400, the sum invested at 15% simple interest per annum is:

Question

Question

This question was previously asked in

SSC CGL 2023 Tier-I Official Paper (Held On: 14 Jul 2023 Shift 3)

Answer 1

Given:

Principal = Rs 10,000

Some part of money lent at 15%

Some part of it lent at 10%

Total interest earned = Rs. 2400

Time = 2 years

Formula Used:

Interest = (Principal × Rate × Time)/100

Calculation:

Let the money lent at 15% be x

Then money lent at 10% be (10,000 - x)

2400 = [(x × 15 × 2)/100] + [(10,000 - x) × 10 × 2]/100

⇒ 2400 = (3x/10) + [(10,000 - x)/5]

⇒ 2400 = (3x + 20,000 - 2x)/10

⇒ 24,000 = 20,000 + x

⇒ x = Rs 4,000

The sum invested at 15% simple interest per annum is 4000.

Shortcut TrickTotal S.I. on 10,000 = (10000 × 2 × R)/ 100 = 2400

R = 12%

F3 SSC Savita 09-10-23 D8