A sum of money at compound interest will amount to 650 at the end of the first year and 676 at the end of the second year. The amount of money is

let the sum of money be Rs P

and Rate of Interest be R% per annum

Compounded Amount = P$$(1 + \frac{R}{100})^n$$

n - number of time periods

Compounded amount after 1 year = P$$(1 + \frac{R}{100})^1$$ = 650.............(1)

Compounded amount after 2 year = P$$(1 + \frac{R}{100})^2$$ = 676.............(2)

Dividing both equation 1 and equation 2

$$(1 + \frac{R}{100})$$ = 1.04

and from here it can be concluded that R = 4% . Now using equation 1 and value of R

P$$(1 + \frac{4}{100})^1$$ = 650

P = Rs 625