Question

3 bags and 4 pens together cost Rs 257 whereas 4 bags and 3 pens together cost R 324.
Find the total cost of 1 bag and 10 pens.

Answer 1

Let the cost of a bag be Rs x and that of a pen be Rs y. Then,

3x + 4y  = 257 ...(i)

4x + 3y = 324 ....(ii)

Multiplying equation (i) by 3 and equation (ii) by 4, we get

9x + 12y = 770 ...(iii)

16x + 12y = 1296 ....(iv)

Subtracting equation (iii) by equation (iv), we get

16x + 9x = 1296 - 771

=> 7x = 525

`=> x = 525/7 = 75`

Cost of a bag = Rs 75

Putting x = 75 in equation (i), we get

`3 xx 75 + 4y = 257`

=> 225 + 4y = 257

=> 4y = 257 - 225

=> 4y = 32

`=> y = 32/4 = 8`

∴Cost of a pen = Rs 8

∴ Cost of 10 pens = 8 xx 10 = Rs 80

Hence, the total cost of 1 bag and 10 pens = 75 + 80 = Rs 155