Karen makes $5 per hour baby-sitting and $12 per hour giving music lessons. One weekend, she worked a total of 18 hours and made $139. How many hours did she spend baby-sitting? F)11
G)9
H)6
J)7​

F) 11

Step-by-step explanation:

We know that she worked 18 hours, and earned $139.

Let's just say that she spent x hours baby-sitting.

If she makes $5 per hour, the total amount of money she earned from baby-sitting would be 5x.

If she spent x hours baby-sitting, that would mean that she spent 18-x hours giving music lessons.

So, the total amount of money she earned from music lessons would be 12(18-x).

Now we can plug this into an equation.

5x + 12(18-x) = 139.

5x + 216 - 12x = 139.

5x - 12x = -77

-7x = -77

x = 11.

This means that she spent 11 hours baby-sitting.

Hope this helps!

answer: a

step-by-step explanation:

10.2 units