A sum doubles in 5 years at simple interest. What is the annual rate?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 20%.
Assume principal = ₹100
If it doubles → amount becomes ₹200
So, interest earned in 5 years = ₹100
Interest for 1 year = 100 ÷ 5 = 20
Rate % = (20/100) × 100 = 20%