Question

A college has raised 75% of the amount it needs for a new building by receiving an average donation of Rs. 600 from the people already solicited. The people already solicited represent 60% of the people the college will ask for donations. If the college is to raise exactly the amount needed for the new building, what should be the average donation from the remaining people to be solicited?

• A. Rs. 300
• B. Rs. 250
• C. Rs. 400
• D. Rs. 500

Hint:

Convert given percentages into absolute amounts using a symbolic variable to solve average donation problems.

Answer 1

The Correct Option is D

Let total people = $P$, total amount needed = $T$.
60% of $P$ have given average Rs. 600, so collected amount = $0.6P \times 600 = 360P$. This is 75% of $T$, so $T = \frac{360P}{0.75} = 480P$. Remaining amount = $480P - 360P = 120P$. Remaining people = $0.4P$. Required average = $\frac{120P}{0.4P} = 300$. Wait — matches Rs. 300, so correct = (1).