Answer:
The amount of money the oldest sister earns per job is $120
The amount of money the middle sister earns per job is $80
The amount of money the youngest sister earns per job is $60
Explanation:
Let
x -----> amount of money the oldest sister earns per job
y -----> amount of money the middle sister earns per job
z -----> amount of money the youngest sister earns per job
we know that
50 percent more means ----> 100%+50%=150%=150/100=1.50
50 percent less means ----> 100%-50%=50%=50/100=0.50
so
-----> equation A
----->
---->
-----> equation B
-----> equation C
substitute equation B and equation C in equation A and solve for x

Multiply by 6 both sides to remove the fraction


Find the value of y
----->

Find the value of z
---->

therefore
The amount of money the oldest sister earns per job is $120
The amount of money the middle sister earns per job is $80
The amount of money the youngest sister earns per job is $60