1 5 books and 7 pens together cost? 7, whereas 7 books and 5 pens toge

1.	1 5 books and 7 pens together cost? 7, whereas 7 books and 5 pens together cost77 Represent this situation inthe form of linear equation in two variables.
Answer» Say, the cost of 1 book is = x rs.and, cost of one pen is = y rs. According to the question,5x + 7y = 79or, 5x x 7 + 7y x 7 = 79 x 7or, 35x + 49y = 553........................(1) Anew, 7x + 5y = 77or, 7x x 5 + 5y x 5 = 77 x 5or. 35x + 25y = 385......................(2) (1) - (2)or, 24y = 168or, y = 7 so, 5x + 7 x 7 = 79or, 5x = 30or, x = 6 So, total cost of one book and one pen is-= (x+y)= 7 + 6 Rs.= 13 Rs.

1 5 books and 7 pens together cost? 7, whereas 7 books and 5 pens together cost77 Represent this situation inthe form of linear equation in two variables.

Answer»

Say, the cost of 1 book is = x rs.and, cost of one pen is = y rs.

According to the question,5x + 7y = 79or, 5x x 7 + 7y x 7 = 79 x 7or, 35x + 49y = 553........................(1)

Anew, 7x + 5y = 77or, 7x x 5 + 5y x 5 = 77 x 5or. 35x + 25y = 385......................(2)

(1) - (2)or, 24y = 168or, y = 7

so, 5x + 7 x 7 = 79or, 5x = 30or, x = 6

So, total cost of one book and one pen is-= (x+y)= 7 + 6 Rs.= 13 Rs.