There was one mess for 30 boarders in a certain hostel. On number of boarders being increased by 10,

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There was one mess for $30$ boarders in a certain hostel. On the number of boarders being increased by $10,$ the expenses of the mess were increased by $Rs.\,40$ per month while the average expenditure per head diminished by $Rs.\,2.$ Find out actual monthly expenses. (in $Rs.$)

A

$390$

B

$410$

C

$360$

D

$480$

Solution

Let, $Rs.\, x$ be the average expenditure for $30$ boarders. $\therefore \quad 30 x+40=(x-2) \times 40 \quad$ or, $\quad x=12$

Hence, actual expenditure $=Rs.\, 12 \times 30=Rs.\, 360$.

Standard 13

Quantitative Aptitude

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