Question

Due to increase of $10\%$ in the price of laptops a shopkeeper reduces its deal of laptop by $10\%$. What was the effect on his expenditure on account of laptops?

• A. $2.50\%$ decrease
• B. $2.20\%$ decrease
• C. $1\%$ decrease
• D. $1.21\%$ decrease

Answer 1

Answer: (C)

Let initial price of a laptop was $XRs$ and number of laptop deals was $Y$.

So, Initial total expenditure $=X\times Y=XYRs$

Now, price increased by $10\%$.

So, New price $=X+10\%ofX=1.1X$

Number of laptop deals decreased by $10\%$

$\therefore Numberoflaptopdeals=Y-10\%ofY=0.9Y$

New total expenditure $=1.1X\times 0.9Y=0.99XYRs$

Decrease in expenditure $=XY-0.99XY=0.01XYRs$

$Decreaseinpercentage=\frac{Decrease\times 100}{InitialExpenditure}=\frac{0.01XY\times 100}{XY}=1\%decrease$