Question

There are 35 students in a hostel. If the number of students increased by 7, the expenses of the mess were increased by Rs. 42 per day while the average expenditure per head decreased by Re. 1. Find out the actual expenditure of the mess.

• A. Rs. 480
• B. Rs. 440
• C. Rs. 52
• D. Rs. 420
• E. None of these

Answer 1

The correct option is D Rs. 420

Let, the original expenditure = Rs. x
Original average expenditure = $\frac{x}{35}$
New average expenditure = $\frac{x+42}{42}$
$\Rightarrow \frac{x}{35}-\frac{x+42}{42}=1\Rightarrow x=420$
$\therefore$ Original expenditure = Rs. 420