Question

By selling pens at $4$ for $Rs.10$, a shopkeeper makes a profit of $20\%$ on the cost price. If he sells them at $Rs.x$ per dozen, he loses $10\%$ on the cost price. Calculate $x$.

• A. $Rs.18.50$
• B. $Rs.22.50$
• C. $Rs.20$
• D. $Rs.18.75$

Answer 1

Answer: (B)

$Rs.22.50$

Let the cost price of one pen is y

Then cost price of 4 pen =4y

Shop keeper makes a profit 20% on 4 pen

$\therefore$ Selling price of 4 pen $=\frac{4y\times 120}{100}=\frac{24y}{5}$

But selling price =Rs 10 (given)

$\therefore \frac{24y}{5}=10\Rightarrow y=\frac{25}{12}$...................(1)

Cost price of one dozen pen =12y

Shopkeeper sell one dozen pen at loss 10% for Rs x

$\therefore \frac{12y\times 90}{100}=x$...........................(2)

Put The $y=\frac{25}{12}$

$\therefore x=\frac{12\times \frac{25}{12}\times 90}{100}$

$\Rightarrow x=22.50$