Question

The cost of 5 exercise books and two pens is Rs 250 . If the cost of one exercise book is Rs 40 , find the cost of 6 pens.​

Answer 1

Rs 150

Explanation:

Solution:

Here, the cost of 1 exercise book = Rs 40

Therefore, the cost of 5 exercise books = 5 × 40 = Rs 250

The cost of ( 5 exercise books + 2 pens ) = Rs 250

or, Rs 200 + cost of 2 pens = Rs 250

or, cost of 2 pens = Rs 250 - Rs 200

= Rs 50

Therefore, cost of 1 pen = Rs 50 ÷ 2

= Rs 25

And , cost of 6 pens = 6 × Rs 25

= Rs 150

Hence, the required cost of 6 pens is Rs 150.

Answer 2

6 pens is 150

Explanation:

Let b = cost of exercise book

p = cost of pen

5 books + 2 pens = 250

5b+2p = 250

We know the cost of one book is 40

b = 40

Substitute this into the first equation

5(40) + 2(p) = 250

Multiply

200 + 2p = 250

Subtract 200 from each side

2p = 250-200

2p = 50

Divide by 2

2p/2 = 50/2

p =25

Each pen is 25

We want the cost of 6 pens

6*25 = 150