Question

Sarah makes $10 an hour babysitting and $5 an hour gardening. her goal is to make $80 a week while working 12 hours. how many hours will Sarah have to work at each job to accomplish her goal

Answer 1

Call b the amount of babysitting hours and 5 the amount of gardening hours.

10b+5g=80
b+g=12

Subtract 5 times the second equation from the first to get:

5b=20
Thus, b=4.  g=12-4, or 8.  Therefore, Sarah spends 4 hours babysitting and the rest gardening.