XAT 2015 — QA & DI Question 12
Compound InterestEasy
In the beginning of the year 2004, a person invests some amount in a bank. In the beginning of 2007, the accumulated interest is Rs. 10,000 and in the beginning of 2010, the accumulated interest becomes Rs. 25,000. The interest rate is compounded annually and the annual interest rate is fixed. The principal amount is:
Answer & solution
- A
Rs. 16,000
- B
Rs. 18,000
Rs. 20,000
- D
Rs. 25,000
- E
None of the above
Solution
Let P be the principal.
By the given conditions,
ââââââââââââââ
Let âââââââ
Thus,
P(X - 1) = 10000 ...(i)
P(X2 - 1) = 25000 ...(ii)
Dividing (ii) by (i),
X + 1 = 5/2
∴ X = 3/2
Substituting value of X in (i), we get
P = Rs. 20,000
Hence, option (c).