1.  There is 60% increase in an amount in 6 years at simple interest. What will be the compound interest of ₹ 12,000 after 3 years at the same rate?
A. ₹ 2160
B. ₹ 3120
C. ₹ 3972
D. ₹ 6240
E. None of these

Answer: Option C

Explanation:

Let P = ₹ 100. Then, S.I. ₹ 60 and T = 6 years.

∴ R = 100 x 60 = 10% p.a.
100 x 6

Now, P = ₹ 12000. T = 3 years and R = 10% p.a.

C.I.
= ₹ 12000 x 1 + 10 3 - 1
100
= ₹ 12000 x 331
1000
= 3972.