Question

3. A shopkeeper earns a profit of 2 by selling a pen and incurs a loss of 50 paise per
pencil and loss of 15 paise per eraser while selling pencils and erasers of old stock. On
a particular day, he earns a profit of *10. If he sold 10 pens and the number of pencils
and erasers he sold are in the ratio 7 : 10, then find the number of pencils and erasers
he sold on that day.​
Please help !

Answer 1

By selling a pen gain is Rs.2

and by selling a pencils, he loses 50 paise

and an eraser, he loses 15 paise

On one day, he gain =Rs.10

On that day he sold 10 pens and pencils and erasers in the ratio of 7:10

On ten pens, his gain =10×2=Rs.20

loss on pencils and erasers =Rs.20−Rs.10=Rs.10=1000 paise

Ratio in pencil and eraser =7:10

Let number of pencils =7x, then eraser =10x

7x×50+10x×15=1000

⇒350x+150x=1000

⇒500x=1000

⇒x=2

Numbe rof penciles =7×2=14

and number of erasers =10×2=20

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