The simple interest on Rs. 25 for 4 months at the rate of 3 paise per rupee per month is equal to how many rupees?

Introduction / Context:
This question uses an interest rate expressed in paise per rupee per month rather than a standard annual percentage. Many bank style problems adopt such wording, and it is important to convert the given rate into a usable percentage or directly work with it in fractional form. The time period is in months, and the principal is small, so the result will also be a small rupee amount.

Given Data / Assumptions:

• Principal (P) = Rs. 25
• Rate = 3 paise per rupee per month
• Time = 4 months

Concept / Approach:
Three paise per rupee per month means that for every rupee of principal, the interest per month is 0.03 rupee. In percentage terms, 3 paise per rupee is 3%, since 1 rupee has 100 paise. Because the period is 4 months, and the problem is clearly monthly, we can work directly at the monthly rate. The simple interest formula in this context is:
SI = P * Monthly rate * Number of months

Step-by-Step Solution:
Monthly rate = 3 paise per rupee = 3% per monthTime = 4 monthsSimple interest = P * rate * time / 100SI = (25 * 3 * 4) / 100SI = (25 * 12) / 100 = 300 / 100SI = Rs. 3
Verification / Alternative check:
Another way is to think in rupees directly. For each rupee, interest per month is 0.03 rupee. For 25 rupees, interest per month is 25 * 0.03 = 0.75 rupee. For 4 months, total interest = 0.75 * 4 = 3 rupees. This matches the earlier calculation and thus confirms the answer.

Why Other Options Are Wrong:
240 paise is Rs. 2.40, which would be the interest if the rate or time were lower. Rs. 1.40 and Rs. 2.20 are even smaller and do not correspond to the given rate and time. Only Rs. 3 is consistent with both methods of calculation.

Common Pitfalls:
Candidates may mistakenly treat 3 paise per rupee per month as 0.03% instead of 3%. Others may forget that the rate is monthly and try to convert it to an annual rate incorrectly. Working directly in terms of rupees per month and then multiplying by the number of months is usually the safest method here.

Final Answer:
The simple interest is Rs. 3.