Selected MCQ

Current Question
A sum trebles itself in 15 years. In how many years will it double?
  • A. 6 years 3 months
  • B. 7 years 9 months
  • C. 8 years 3 months
  • D. 9 years 6 months
Correct Answer: B
Explanation:
Using compound growth relation gives ≈ 7 years 9 months.
Related Question 1
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 2
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 3
A sum doubles in 4 years. In how many years will it triple?
  • A. 16
  • B. 8
  • C. 12
  • D. 20
Correct Answer: C
Explanation:
Using a compound growth relation.
Related Question 4
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 5
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.