Question

The ratio of income of two person is 5 :3 and expenditure 9:5 .if they save 1800 their invome is?

Answer 1

let income of 1st person is x
income of 2nd person is y
5/3 = x/y
5y = 3x

let expenditure of 1st person is x' and 2nd is y'
x'/y' = 9/5
9y' = 5x'

also both save equally I.e income -expenditure is same for both
y-y' =1800. Equation 1
x-x' = y- y'
On solving
5y = 6y'
put this in equation 1
we get y' = 9000 and y =10800
Income of y is 10800 and x is 18000