Principal Amount = Rs 25,000
Rate of interest = 12 p.c.p.a.
Let interest on principal Rs 25,000 be Rs x
By taking ratio of the interest to the principal for both, we obtain an equation
Amount to be returned to the bank at the end of the year = Principal Amount + Interest
= Rs 25,000 + Rs 3,000
= Rs 28,000
Ahmad Chacha has to return Rs 28,000 to the bank at the end of the year.