Compound Interest - General Aptitude

Q1:

If the simple interest on a sum of money for 2 years at 5% per annum is Rs. 50, what is the compound interest on the same at the same rate and for the same time?

A Rs. 51.25

B Rs. 52

C Rs. 54.25

D Rs. 60

ANS:A - Rs. 51.25

Sum = Rs. 50 x 100 = Rs. 500.
2 x 5
Amount
= Rs. 500 x 1 + 5 2
100
 
= Rs. 500 x 21 x 21
20 20
  = Rs. 551.25
 C.I. = Rs. (551.25 - 500) = Rs. 51.25