The monthly incomes of A and B are in the ratio 5 : 4 and their monthly expenditures are in the ratio 7 : 5. If each saves Rs.9000 per month, find the monthly income of each.

Let the monthly incomes of A and B are 5x and 4x respectively. Also their monthly expenditures are 7y and 5y respectively.


According to question -


Savings of family A = 5x - 7y = 9000.....(1)


Savings of family B = 4x - 5y = 9000.....(2)


Subtracting equation (2) from (1), we get -


x = 2y.....(3)


Substitute the value of x in equation (1), we get -


y = 3000


Substitute the value of y in equation (3), we get -


x = 6000


Thus, the monthly income of A = 5x = Rs.30000


and, the monthly income of B = 4x = Rs.24000


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