Question

the price of 4 books and 10 pens is ₹ 100 and the price of 7 books and 9 pens cost ₹ 158 , then find the cost of 2 books and 5 pens.​

Answer 1

let book = x and pen = y

then

(4x+10y=100)*9

(7x+9y=158)*10

36x+90y=900

70x+90y=1580

36x+90y=900

-_____________

            34x=680

                 x=20

and for y

4*20+10y=100

80+10y=100

10y=20

y=2

so the cost of 2 books is 2*20=40 rs

and the cost of 5 pens is 5*2=10 rs

total cost is 40+10 = 50