Question

Mohan spent $25\%$ of his monthly earning on magazines. Out of the remaining amount amount he spent $75\%$ on the hostel and college fees. If he had Rs. $120$ at the end of the month, find how much money he has received from his father in that month?

• A. Rs. $1000$
• B. Rs. $1260$
• C. Rs. $640$
• D. Rs. $850$

Answer 1

The correct option is C Rs. $640$

Let the monthly income be $=x$

Expenditure on magazine $=25x=\frac{1}{4}x$

So balance amount $=x-\frac{x}{4}=\frac{3}{4}x$

And hostel and college expense $=\frac{3}{4x}\times \frac{75}{100}=\frac{9x}{16}$

So balance amount he had $=\frac{3}{4}x-\frac{9x}{16}$

$\frac{12x-9x}{16}-\frac{3x}{16}$

As per the problem $=\frac{3x}{16}=240$

or $3x=120\times 16$ or $x=\frac{120\times 16}{3}=Rs.640$