Question

5 books and 7 pens together cost Rs 79 whereas 7 books and 5 pens together cost Rs 77. Find the total cost of 1 book and 2 pens.

Answer 1

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

Multiplying equation (i) by 5 and equation (ii) by 7, we get

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

Hence, the total cost of 1 book and 2 pens = 6+14 = Rs 20