Question

Mari and Jen each work 20 hours a week at different jobs. Mari earns twice as much as Jen. Together they can earn $480. How much does each girl earn in a week?

Answer 1

Hey there!

In word problems, remember that not every number they give you is important. For example, here, they tell you that they both work 20 hours a week. This information isn't important in creating an equation to represent the situation. 

Let's say that x is the amount that Jen makes. Therefore, 2x will be the amount that Mari makes since she makes twice as much as Jen. Together, the amounts they make adds up to 480, meaning that the entire equation will be:

x + 2x = 480

All we need to do is solve this for x, plug x back into the equation, and solve. 

1x + 2x = 480 (combine 1x and 2x)
3x = 480 (divide both sides by 3)
x = 160

Now, plug 160 in for x in the original equation to check and solve for how much Mari makes (she's represented by 2x). 

160 (Jen) + 2(160) (Mari) = 480
160 (Jen) + 320 (Mari) = 480
480 (Jen + Mari) = 480

Jen makes $160 a week and Mari makes $320 a week. 

Hope this helped you out! :-)