Question

The monthly incomes of A and B are in the ratio 9:7 and their monthly expenditures are in the ratio of 4:3 . If each saves 1600 per month, find the monthlly income of each.

Answer 1

let incomes of both persons be 9x and 7x
and their expenditures be 4y and 3y
then
9x-4y=1600---eq1
7x-3y=1600----eq2
multiplying eq1 with 3 and eq2 with 4,we get
27x-12y=4800--eq3
28x-12y=6400--eq4
subtracting eq3 from eq4,we get
x=1600
since 7x-3y=1600
7(1600)-3y=1600
3y=1600x6
y=3200
then income of x and y is 9(1600),7(1600)
I.e 14400,11200
exp being 4(3200),3(3200),
I.e 12800,9600

Answer 2

Answer:

let incomes of both persons be 9x and 7x

and their expenditures be 4y and 3y

then

9x-4y=1600 ---eq1

7x-3y=1600 ----eq2

multiply eq1 with 3 and eq2 with 4,

27x-12y=4800 --eq3

28x-12y=6400 --eq4

subtract eq3 from eq4,

x=1600

since

7x-3y=1600

7(1600)-3y=1600

3y=1600x6

y=3200

then income of x and y is

Income ofX=9(1600) =14400★

Income of Y= ,7(1600)=11200★