If the compound interest on a sum for 2 years at 121% per

If the compound interest on a sum for 2 years at 12 1 % per annum
2
is ₹ 510, the simple interest on the same sum at the same rate for the same period of time is :

Here , Principal ( P ) = ? , Compound Interest ( CI ) = ₹ 510 , Rate ( R ) = ( 25 / 2 )% , Time = 2 years

C.I. = P			1 +	R		^T	− 1
				100

⇒ 510 = P			1 +	25		²	− 1
				200

⇒ 510 = P			1 +	1		²	− 1
				8

⇒ 510 = P		81	− 1
		64

⇒ 510 = P		81 - 64
		64

⇒ P =	510 × 64	= ₹ 1920
	17

∴ S.I. =	P × R × T
	100

∴ S.I. =	1920 × 2 × 25	= ₹ 480
	100 × 2

Second Method to solve this question :

Here, C.I. = ₹ 510 , R = 12	1	%, S.I. = ?
	2

With the help of given formula ,

C.I. = S.I.		1 +	R
			200

510 = S.I.		1 +	25
			400

510 = S.I.			425
			400

S.I. =	510 × 400	= ₹ 480
	425

If the compound interest on a sum for 2 years at 12	1	% per annum
	2