Prices register an increase of 10\% on foodgrains and 15\% on other items of expenditure. If the ratio of an employee's expenditure on foodgrains and other items be 2: 5, by how much should his salary be increased in order that he may maintain the same level of consumption as before, his present salary being ₹ 2590?
(a)₹ 323.75
(b)₹ 350
(c)₹ 360.50
(d)None of these
Answer
Answer (as printed): D
Explanation
Let expenditures on food and other items be ₹ $2 x$ and ₹ $5 x$. Then, $2 x+5 x=2590$ or $x=370$. So, expenditure on food $=₹(2 \times 370)=₹ 740$. Expenditure on other items $=₹(5 \times 370)=₹ 1850$. New expenditure $=110 \%$ of $₹ 740+115 \%$ of $₹ 1850$ $$\begin{aligned} & =₹\left(\frac{110}{100} \times 740+\frac{115}{100} \times 1850\right) \\ & =₹(814+2127.50)=₹ 2941.50 . \end{aligned} \text { ∴ } \text { Desired increase }=₹(2941.50-2590)=₹ 351.50 .$$
Explanation as extracted from the printed page; notation may be imperfect.