Trevor tutors french for $15 and hour and scoops ice cream for $10 an hour. he is going to work 15 hours this week. at least how many hours does he need to tutor to make more than $180? ? hours

Total number of hours = 15

Let the hours spent tutoring french be x.

Therefore hours spent on scooping ice cream = (15 - x)

Amount:    Tutoring french is $15 an hour, total for x hours = 15x

For scooping ice cream  it is $10 an hour   10*(15 - x) = 150 - 10x

To make more than $180

15x  + (150 - 10x)  > 180

15x + 150 - 10x > 180

15x - 10x > 180 - 150

5x > 30

x > 30/5

x > 6

So he needs to tutor more than 6 hours in order to make more than $180