1.  A person borrowed ₹ 500 @ 3% per annum S.I. and ₹ 600 @ 4% per annum on the agreement that the whole sum will be returned only when the total interest becomes ₹ 126. The number of years, after which the borrowed sum is to be returned, is :
A. 2
B. 3
C. 4
D. 5

Answer: Option B

Explanation:

Let the time be X years. Then,

500 x 3 x X + 600 x 9 x X
100 100 x 2

<=> 15X + 27X = 126
<=> 42X = 126 <=> X = 3.
Required time = 3 years.