A certain sum becomes 4 times of itself in 5 years at a rate of simple interest. In 15 years in will become how many times of itself at the game rate of simple interest?
Answer & explanation
Correct answer: option 2
We know ,
Simple Interest = \(\frac{Principal ×Rate × Time }{100}\)
Amount = Principal + Interest
Let principal = P
ATQ,
A sum becomes 4 times of itself in 5 years i.e. 4P
Simple interest in 5 years = 4P - P = 3P
So , 3P = \(\frac{P × Rate × 5 }{100}\)
Rate = 60% In 15 years , Sum becomes = P + \(\frac{P × 60× 15 }{100}\)
= p + \(\frac{P × 3× 15 }{5}\)
= P + 9P
= 10P
So , In 15 years sum becomes 10 times of itself.