- Home
- Std 13
- Quantitative Aptitude
4.Average
hard
There were $35$ students in a hostel. If the number of students increases by $7 ,$ the expenses of the mess increase by $Rs.\,42$ per $day$ while the average expenditure per head diminishes by $Rs.\,1$ Find the actual expenditure of the mess. (in $Rs.$)
Solution
Suppose, the average expenditure was $Rs.\, x$
Then, total expenditure $=35 x$
When $7$ more students join the mess, total expenditure $=35 x+42$
Now, the average expenditure
$=\frac{35 x+42}{35+7}=\frac{35 x+42}{42}$
Now, we have $\frac{35 x+42}{42}=x-1$
$\therefore \quad x=12$
Thus, the actual expenditure of the mass $=35 \times 12=2420$
Std 13
Quantitative Aptitude
