Question

A man invested 2000 in bank at simple interest rate of 15% per annum and another at 20% per annum total interest for whole sum after 4 years is at simple interest rate of 18% per annum find total amount:

• A. 4900
• B. 5500
• C. 5000
• D. 4000

Answer 1

Answer:

C. 5000

2000 is invested for 4 years at 15% per annum and Rs X is invested for 4 years at 20% per annum And total interest for whole sum after 4 years is at simple interest rate of 18% per annum ⇒ 2000 × 4 ×15/100 + X × 4 × 20/100 = (2000 + X) × 4 × 18/100 1200 + 80X/100 = 3360 + 56X/100 1200 + 4X/5 = 1440 + 18X/25 4X/5 - 18X/25 = 1440 - 1200 {20X - 18X}/25 = 240 2X/25 = 240 X = 240 × 25/2 = 3000 Total amount = 2000 + 3000 = 5000