Question

A certain sum becomes Rs 840 in 3 years and Rs 1200 in 7 years at simple interest. What is the value (in Rs.) of principal?

• A. 520
• B. 570
• C. 620
• D. 670

Answer 1

Answer:

B. 570

principal = P SI after 3 years = 840 - P SI after 7 years = 1200 - P (840 - P) × 100/(R × 3) = (1200 - P) × 100/(R × 7) 7 × (840 - P) = 3 × (1200 - P) 5880 - 7P = 3600 - 3P 4P = 2280 P = 570