There are 35 students in a hostel. If number of students increased by 7, expenses of mess were incre

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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 $Rs.\,1$, Find out the actual expenditure of the mess. (in $Rs.$ )

A

$480$

B

$440$

C

$520$

D

$420$

Solution

Let, the original expenditure $=Rs. x$

Original average expenditure $=\frac{x}{35}$

New average expenditure $=\frac{x+42}{42}$

$\Rightarrow \frac{x}{35}-\frac{x+42}{42}=1 \Rightarrow x=420$

Original expenditure $=Rs. 420$

Standard 13

Quantitative Aptitude

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