Question

Mia worked 40 hours at her two jobs last week. She earns $20 per hour at her weekday job and $18 per hour at her weekend. She earned $770 in all. How many hours did she work at each job?

Answer 1

Mia worked fifteen hours at her weekend job and worked twenty-five hours at her weekday job.

Explanation:

There are several ways to solve this system of equations, and my favorite way is the elimination, so I'm going to explain how to solve by elimination. Let x represent the hours of her weekday job, and y represents the hours of her weekend job.

Step 1: Come up with your system of equations.
20x+18y=770
x+y=40

Step 2: Multiply the second equation by 20 to get
20x+18y=770
20x+20y=800
Step 3: Subtract *20 comes from the weekday job
20x+18y=770 18 comes from the weekend job
20x+20y=800 770 comes from the total amnt.
=------------------------ earned.
-2y=-30
Step 4: Divide by -2 in order to isolate y.
-2y = 30
---- ----

-2 -2
Step 5: Simplify.
y=-15
Step 6: Substitute y=15 into y+x=40.
15+x=40
Step 7: Subtract 15 from both sides.
x=25

Answer 2

x = 25

Explanation:

x = # of hrs he worked at his weekday job

w = # of hours he worked at his weekend job

25+ x = 40y = 40 - 25 = 15.

Therefore, Mia worked for 25 hours at his weekday job and 15 hours at his weekend job.

w + x = 40

20x + 18w = 770

18(x + w = 40) = 18x + 18w = 720

(20x + 18w = 770) - (18x + 18w = 720)

2x=50

x=25