The compound interest on a certain sum for 2 years at 10%

The compound interest on a certain sum for 2 years at 10% per annum is Rs. 525 . The simple interest on the same sum for double the time at half the rate percent per annum is :

Given that , C.I. = Rs. 525 , Time = 2 years , Rate = 10%
Using the given formula ,

C.I. = P			1 +	R		^T	− 1
				100

⇒ 525 = P			1 +	10		²	− 1
				100

⇒ 525 = P		121	− 1
		100

⇒ 525 =	P × 21
	100

⇒ P =	525 × 100	= Rs. 2500
	21

Again, new rate = 5% per annum

∴ S.I. =	Principal × Time × Rate
	100

S.I. =	2500 × 5 × 4	= Rs. 500
	100