7groups of 4 students = total of 28 students $6100=28×$45(h)−$200

Problem: Veronica teaches French in groups of four students. She rents a room for $200 per month. She charges $45 per hour per student. Veronica teaches seven groups of students, and her net earnings per month are $6,100.

Given:
6,100 = net earnings
Net earnings mean that the rent has already been deducted.
200 = rent per month
45 = rate per student per hour
28 = number of students (7 groups of 4 students)

Find: number of hours each student learns French in a month

28(45h) = 6100 + 200
1260h = 6300
1260h/1260 = 6300/1260
h = 5    

Each student learns French 5 hours in a month.