Question

Monthly incomes of two persons are in the ratio 4 : 5 and their monthly expenses are in

the ratio 7 : 9. If each saves ` 50 per month find their monthly incomes.

Answer 1

Let the income of two persons be 4x and 5x and their expenses be 7y and 9y. 

Then, 4x - 7y = 50 ... (i) 

and 5x - 9y = 50 ... (ii) 

Solving Eqs. (i) and (ii). we get

x = 100 and y = 50 

Therefore, The income of persons are Rs.400 and Rs.500

Answer 2

Expenses = 7:9

Income = 4:5

Savings 50

Income = expense + savings

let income be x

4/5 = (7x+50) / (9x+50)

4(9x+50) = 5(7x+50)

36x+200 = 35x+250

x = 50

so their incomes are

(7x+50) = 7(50) + 50 = 400 salary of 1st person

(9x+50) = 9(50) + 50 = 500 salary of second person