MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Rani Abbakkadevi

John bought s...

Question

John bought some pencils, erasers and pens from a store. The ratio between the number of pencils and the number of erasers is the same as between the number of erasers and the number of pens bought by him. If he bought 12 pencils and 3 pens, find the number of erasers he bought.

Open in App

Solution

Calculate the number of erasers:
Let, the number of erasers he bought be $x$ .
According to the question,
$\frac{N u m b e r o f p e n c i l s}{x} = \frac{x}{N u m b e r o f p e n s} \Rightarrow \frac{12}{x} = \frac{x}{3} (S u b s t i t u t i n g t h e g i v e n v a l u e s) \Rightarrow x \cdot x = 12 \cdot 3 (C r o s s m u l t i p l y i n g b o t h s i d e s) \Rightarrow x^{2} = 36 ∴ x = \pm 6 (T a k i n g s q u a r e r o o t o n b o t h s i d e s)$
Since the number of erasers cannot be negative, therefore, the number of erasers is 6.
Final Answer: John bought 6 erasers.

Suggest Corrections

thumbs-up

0

Similar questions

Q. I bought 5 pens, 7 pencils and 4 erasers. Rajan bought 6 pens, 8 erasers and 14 pencils for an amount which was half more what I had paid. What percent of the total amount paid by me was paid for the pens?

Q. I bought 5 pens, 7 pencils and 4 erasers Rajan bought 6 pens, 8 erasers and 14 pencils for an amount which was half more what I had paid What percent of the total amount paid by me was paid for the pens?

Q. A shopkeeper earns a profit of Rs 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 Rs 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.

2

4

8

R s . 12

and the cost of

8

10

4

R s . 36

. How much will

3

3

3

Q. A shopkeeper earns a profit of

R s 2

by selling a pen and incurs a loss of

50 p a i s e

per pencil and loss of

15 p a i s e

per eraser while selling old stock. On a particular day, he earns a profit of

R s 10

10

pens and number of pencils and erasers he sold are in the ratio

7 : 10

, then find the number of pencils and eraser he sold that day.

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Rani Abbakkadevi

HISTORY

Watch in App

explore_more_icon

Explore more

Rani Abbakkadevi

Standard VII History

Join BYJU'S Learning Program

CrossIcon