Correct Answer - Option 3 : 20 yr
Given
A certain sum of money doubles itself in 10 yr. In how many years will it become 3 times at the same rate of simple interest
Concept used
Simple interest
Calculation
Let sum = Rs.x
Si = x
Time = 10 years
Rate = (interest × 100) / Principal × time
Rate = (100x) / 10x
Rate = 10%
Now sum = x, Si = 2x, Rate = 10%
Time = (interest × 100) / Principal × rate
Time = (2x × 100) / 10x
Time = 20 years.