
Answer:
Step-by-step explanation:
Amount charges by plumber =  £ 167.00
Call out fee = £ 18.50
Charge excluding the call out fee = 167 - 18.50 = £ 148.50
Total hours worked = 9 hours
Charge per hour = charge excluding the call out fee ÷ total hours
              = 148.50 ÷ 9
             = £ 16.50