Answer:
18 hours.
Explanation:
Gebe rents a piano for $49 per month.
He earns $15 per hour for giving piano lessons to students.
Let his earning for x hour = 15x
15x + 49 = 316
15x = 316 - 49
15x = 267
x =
![(267)/(15)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/1z7hv5cw3x143ekvzh018rrldb2s5cvf0r.png)
x = 17.8 hours ≈ 18 hours
Gebe must give 18 hours lessons to earn a profit of $326.