Selected MCQ

Current Question
A sum doubles itself in 5 years at compound interest. In how many years will it become eight times?
  • A. 7 years
  • B. 10 years
  • C. 15 years
  • D. 20 years
Correct Answer: C
Explanation:
8 = 2³ ⇒ 3 × 5 = 15 years.
Related Question 1
A sum becomes triple in 3 years at compound interest. In how many years will it become 9 times?
  • A. 18
  • B. 12
  • C. 9
  • D. 6
Correct Answer: D
Explanation:
Growth is exponential → 6 years.
Related Question 2
A sum of money doubles in 5 years at simple interest. In how many years will it become four times ____.
  • A. 10 years
  • B. 12 years
  • C. 15 years
  • D. 20 years
Correct Answer: C
Explanation:
Doubling means 100% interest in 5 years → quadruple = 300% → 15 years.
Related Question 3
A sum of money doubles itself in 5 years at simple interest. What is the rate of interest?
  • A. 10%
  • B. 20%
  • C. 25%
  • D. 40%
Correct Answer: B
Explanation:
Doubling ⇒ SI = principal → rate = 100/5 = 20%.
Related Question 4
A sum becomes Rs. 1210 in 2 years at 10% per annum compound interest. What is the principal?
  • A. Rs. 1000
  • B. Rs. 1100
  • C. Rs. 1200
  • D. Rs. 900
Correct Answer: A
Explanation:
1000 × (1.1)² = 1210.
Related Question 5
A sum is put at simple interest for 2 years. If compounded annually, it becomes Rs. 750. What is the original sum?
  • A. Rs. 750
  • B. Rs. 700
  • C. Rs. 940
  • D. Rs. 820
Correct Answer: A
Explanation:
Equal amounts indicate no compounding effect.