1.  The difference between simple and compound interests compounded annually on a certain sum of money for 2 years at 4% per annum is Re. 1. The sum (in ₹) is:
A. 625
B. 630
C. 640
D. 650

Answer: Option A

Explanation:

Let the sum be Rs. x. Then, C.I.

= x 1 + 4 2 - x = 676 x - x = 51 x.
100 625 625

S.I. = x x 4 x 2 = 2x .
100 25

∴ 51x - 2x = 1
625 25

⇒ x = 625.