There is 60% increase in an amount in 6 years at simple interest. What will be the compound interest of tk.12000 After 3 years in same rate?

A tk 2160

B tk 3120

C tk 3972

D tk 6240

Correct Answer: Option C

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

So, R = 60/6= 10%

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

SO, Amount= tk. [12000x {(1+10/100)3}]

= tk. 12000x (1331/1000)

= 15972

So interest = 15972- 12000 = 3972