The compound interest on a certain sum of money for 2 years at 10% per annum is Rs. 420. The simple interest on the same sum at the same rate and for the same time will be?
Correct Answer: Rs. 400
Explanation:
Let the principal be P. Then,
∵ P(1 +10/100)2 - P =420
⇒ P(121 - 100/100) =420
⇒ P = Rs. 2000
∴ Requared S.I.= Rs.(2000 x 2 x 10)/100
= Rs. 400
