Question

the ratio of incomes of two person is9:7 and the ratio of their expenditure is4:3.if each of them manages to save rs.2000 per month ,find their monthly income

Answer 1

let the income of two person be x and

let the expenditure of two person be y.

according to the condition of the problem,

the equations are,

9x - 4y = 200  eq (1)

7x - 3y = 200  eq (2)

by using elimination method, we obtain

eq (1) * 3 = 27x - 12y = 600

eq (2) * 4 = 28x - 12y = 800

we get x = 200

x = 200 = 7x - 3y = 200

  = 7 (200) - 3y = 200

  = 1400 - 3y = 200

  = -3y = 200 - 1400

  = -3y = -1200

  y = 400

hence monthly income of two persons are 200 and 400 respectievly.