Question

5 books and 7pen together cost 285Rs .4books and 4 pens together cost Rs 220.monu purchased 3books and 5pens and calculated total costto be Rs195tothe shopkeeper. Shopkeper rechecked and returned some money to manu .
1.how much money did the shopkeeper returned to monu

Answer 1

1 book is 50 and 1 pen is 5.

Answer 2

Let us assume the cost of a book is Rs b and cost of a pen is Rs p.

Given:

5b + 7p = 285Rs --------------1

Again given that

4b + 4p = 220Rs ---------------2

This can be rewritten as

b + p = 55 -------- 2a

 Multiplying equation 2a by 5, we get

 5b + 5p = 275 ------- 2b

Subtracting equation 2b from 1, we get

 5b + 7p = 285

-5b - 5p = -275

--------------------

2p = 10

 Or p = 10/2 = 5

Substituting the value of p = 5 in b + p = 55, we get

b + 5 = 55

or b = 50

 Since Monu bought 3 books and 5 pens, his cost was

3 x 50 + 5 x 5 = 150 + 25 = 175.

Monu gave the shopkeeper `195, the shopkeeper gave him back, 195 – 175 = `20.

1. The amount returned by the shopkeeper was `20.