Question

In what time will the simple interest on a certain sum be of the principal at 5% per annum
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Answer 1

Solution :-

Let the principal amount be Rs. 100

Simple interest should be three fourth (3/4th) of the principal.

So, the simple interest = (100*3)/4 = Rs. 75

So, 

P = Rs. 100 ;  Rate of Interest = 6 % Time = ? Simple Interest = Rs. 75

Simple Interest = (P*R*T)/100

⇒ 75 = (100*6*T)/100

⇒ 75*100 = 600T

⇒ T = 7500/600

⇒ T = 25/2 or 12 years and 6 months

 

So, in 12 years and 6 months the simple interest on a certain principal will be three-fourth of that principal @ 6 % per annum.

Answer.