Question

The ratio income of a and b is 9:7 and the ratio of expenditures is 4:3 if each of them manages tovsave rs 2000 per month find the monthly income of a

Answer 1

HEY DEAR ...

Let their salaries be 9x and 7x
let their expenditure be 4y and 3y

so,

ATQ
9x-4y=200—(1)
7x-3y=200—(2)

so,

from (1)
x=(200+4y)/9—(3)

put x in (2)
7[(200+4y)/9]-3y=200
(1400+28y)/9-3y=200
(1400+28y-27y)/9=200
y+1400=1800
y=400

now put y in (3)
x=(200+4×400)/9
x=(200+1600)/9
x=1800/9
x=200

so,
salary of first person=9×200=1800 rs
salary of second person=7×200=1400 rs

HOPE , IT HELPS ...