Question 1073108
x + y = 9000


x represents the amount of money that person A makes, i.e. his income.
y represents the amount of money that person B makes, i.e. his income.


person A spends 60% of his income.
therefore, what he has left is 40% of his income.
this represent his savings.
this can be shown as .4x


person B spends 80% of his income.
therefore, what he has left is 20% of his income.
this represents his savings.
this can be shown as .2y


you are given that their savings are equal.


.4x = .2y


you have 2 equations that need to be solved simultaneously.


they are:


x + y = 9000
.4x = .2y


this can be solved by substitution fairly easily.


solve for y in the first equation to get:


y = 9000 - x


replace y with 9000 - x in the second equation to get:


.4x = .2 * (9000 - x)


simplify to get:


.4x = 1800 - .2x


add .2x to both sides of this equation to get:


.6x = 1800


divide both sides of this equation by .6 to get:


x = 1800 /.6 = 3000


since x + y = 9000, then y = 6000


you have:


income of person A is 3000
income of person B is 6000


person A spends 60% of 3000 and is therefore left with 40% of 3000 which is equal to 1200.


person B spends 80% of 6000 and is therefore left with 20% of 6000 which is equal to 1200.


their savings are equal.


you are asked for the income of x.


x represents the income for person A which is equal to 3000.