helmet = $5
houly rent $8.50
total pay = $47.50
number of hours = a
ok
Equation
total payment = cost of rent x number of hours + rent of the helmet
47.50 = 8.5a + 5
Solve for a
47.50 - 5 = 8.5a
42.5 = 8.5a
a = 42.5/8.5
a = 5
He rented the hour for 5 hours