Question

the ratio of income of two persons is 11:7 and the ratio of thier expenditure is 9:5. if each of them manaages to save Rs.400 per month, find their monthly income.

Answer 1

let the income of first person be 11x
and his expenditure be 9x
let the income of second person be 7x
and his expenditure be 5x
according to the question
11x-9x=400
x=200
Or
7x-5x=400
x=200
so their income is

First person=2200
second person=1400

Answer 2

Soln:

Let their incomes are: 11K & 7K.

Let their expenditures are : 9M & 5M

Hence, their savings are: 11K - 9M & 7K - 5M

according to question:

11K - 9M = 400 ------------ ( 1 )

7K - 5M = 400 ------------- ( 2 )

Operates: (2) x 9 - (1) x 5 => 63K - 55K = 3600 - 2000

=> 8K = 1600

=> K = 200

Hence, their monthly incomes are: 11K & 7K

I.e, 11x200 = ₹ 2200 & 7x200 = ₹ 1400