Question

16. Raju bought 5 notebooks and 4 pens for 148 rupees. But he needed only 4 notebooks and 5 pens .It would cost 140 rupees only. What is the price of a notebook? What is the price of a pen? ​

Answer 1

Step-by-step explanation:

let, the price of a notebook is = x

& the price of a pen is = y

A/Q,

5x + 4y = 148

=> 5x = 148 - 4y

=> x = (148 - 4y)/5 — equation i

again,

4x + 5y = 140

=> 4 {(148 - 4y)/5} + 5y = 140 [from eqn i]

=> (592 - 16y)/5 + 5y = 140

=> (592 - 16y + 25y)/5 = 140

=> 592 + 9y = 140 × 5

=> 9y = 700 - 592

=> y = 108/9 = 12

From eqn i,

x = (148 - 4y)/5 = (148 - 4 × 12)/5 = (148 - 48)/5 = 100/5 = 20

•°• the price of a notebook is = 20 rs

& the price of a pen is = 12 rs.