Question

12
On a certain sum, compound interest obtained after 8 years is Rs 5000 at 20% rate of compound
interest. Find the compound interest obiained after 12 years.

Answer 1

Answer:

Let P be the Sum and x be C.I after 12 yrs.

C.I = Rs 5000 n = 8 yrs.

We know C.I = P{ ( 1+ r/100 )^n - 1 }

Putting values in equation above

5000 = P{ ( 1 + 20/100 ) ^8 - 1}………(1)

x = P{ ( 1 + 20/100 ) ^12 - 1 }… … … . (2)

Dividing (2) by (1)

x/5000 = P{ (6/5) ^12 - 1 } / P{ (6/5) ^8 - 1}

x/5000 = ( 8.9161 - 1 ) / ( 4.300 - 1) = 7.9161/ 3.300

x/5000 = 2.4 = 2.4 × 5000 = Rs 12000 Ans.