Question

The price of a commodity is increased by $40\%$. By what per cent should a consumer reduce his consumption so that his expenditure on the commodity remains constant?

• A. $25\%$
• B. $28.57\%$
• C. $30\%$
• D. $42.57\%$

Answer 1

The correct option is B $28.57\%$

Let initially consumers consumes $x$ amount in $RS.100x$

after price increase by $40\%$,

Now consumers consumes $y$ amount in $RS.140y$

According to the question, $100x=140y$

$⟹\frac{y}{x}=\frac{100}{140}$

$⟹1-\frac{y}{x}=1-\frac{100}{140}$

$⟹\frac{x-y}{x}=\frac{140-100}{140}$

$\%$Decrease in comsumption$=\frac{x-y}{x}\times 100=\frac{40}{140}\times 100=28.57\%$