Question

class 10 chapter 3 example 11. solve by substituting method only only substituting method if u don't know don't answer​

Answer 1

let their income be 9x and 7x

let their expenditure be 4y and 3y

According to the question

9x-4y = 2000 --->(1)

7x-3y = 2000 ---->(2)

from(1)

x= 2000+4y/9------>(3)

on putting x in (2) we get

7×(2000+4y/9)-3y = 2000

(14000+28y/9)-3y = 2000

14000+28y-27y/9 = 2000

14000+y = 18000

y = 18000-14000

y = 4000

Now put y in (3)

x = 2000+4×4000/9

= 2000+16000/9

= 18000/9

= 2000

So,

income of first person =9×2000 = Rs 18000

income of second person = 7×2000 = Rs 14000