A sum of money invested at compound interest amounts to

A sum of money invested at compound interest amounts to ₹ 650 at the end of first year and ₹ 676 at the end of second year. The sum of money is :

As per the given in question ,
Interest on ₹ 650 for 1 year = 676 – 650 = ₹ 26

So, r =	26	× 100
	650

⇒ r = 4% per annum

=	650	= 650 ×	25	= ₹ 625
	( 26/25 )		26

Using the given formula :
Here, b – a = 1 , B = Rs 676, A = ₹ 650

R% =		B	− 1		× 100%
		A

R% =		676	− 1		× 100%
		650

R% =		676 −650		× 100%
		650

R% =	26	× 100%
	650

R% =	100	= 4%
	25

Amount = P		1 +	R		¹
			100

650 = P		1 +	4
			100

⇒ P =	650 × 100	= ₹ 625
	104

Note : A sum at a rate of interest compounded yearly becomes ₹ A, in n years and ₹ A₂ in (n + 1) years,

then P = A₁		A₁		ⁿ
		A₂