Plz help in solve this problem?

if the ratio of the incomes of two persons is 9 : 7 and ratio of their expenditures is 4 : 3. Each of them saves Rs. 2000 per month. Find their monthly income.
You can solve this by using a system of equations.



Ratios imply that the actual numbers are probably larger than the numbers in the ratio, but that they are multiplied by a common factor. Call x the factor by which their incomes will by multiplied and call y the factor by which their expenditures will be multiplied.



income - expenditures = savings



9x - 4x = 2000

7x - 3x = 2000



this shows that both people end up with $2000 savings.



Now to solve, mulitply the top equation by 3 and the bottom equation by -4:



3(9x - 4x = 2000)

-4(7x - 3x = 2000)



27x - 12x = 6000

-28x 12x = -8000



Add them:

-x = -2000

so x = 2000



Now multiply both 9 and 7 by 2000 to get their monthly incomes:



9*2000 = $18000



7*2000 = $14000



Those are your answers.

You can proceed to solve for y and check your answer.



You should get y=4000



so 18000 - 4(4000) = 18000 - 16000 = 2000



and 14000 - 3(4000) = 14000 - 12000 = 2000



Yay!
Let the smaller income be x. Then the larger income is (9/7) x. Let the smaller expenditure be y. Then the larger expenditure is (4/3) y. Then we get these equations:



For the larger income:



(9/7) x - (4/3) y = 2000

21 [(9/7) x - (4/3) y] = 21 (2000)

*** 27x - 28y = 42000.



For the smaller income:



x - y = 2000 ---