Question

Prices of food grains and other items of consumption have risen by $10\%$ and $15\%$ respectively. If the ratio of an employee's expenditure on food grains and other items is $2:5,$ by how much should his salary be increased so that he may maintain the same level of consumption as before, assuming that his present salary is $3500$ rupees?

• A. $300$ rupees
• B. $350$ rupees
• C. $375$ rupees
• D. $475$ rupees

Answer 1

The correct option is D $475$ rupees

Let the man's original expenditure on foodgrains and other items be $2x$ and $5x$ respectively.
Then, total original expenditure $=2x+5x=7x$
Total new expenditure $=(110\%\text{of}2x+115\%\text{of}5x)$
$=(\frac{11x}{5}+\frac{23x}{4})=\frac{159x}{20}$
The ratio of increased expenditure to original expenditure $=\frac{159x}{20}\times \frac{1}{7x}=\frac{159}{140}$
$\therefore$ Required salary $=\frac{159}{140}\times 3500=3975$ rupees
Desired increase in salary $=3975-3500=475$ rupees