Question 805787
A plumber charges Php150 per hour for his labor and Php120 per hour for his assistant. On a repair job the bill was Php3440 with Php2460 for labor and Php980 for parts. If the assistant worked for two hours less than the plumber, how many hours did each work?


Total bill = 3440 
parts = 980
labor bill = 2460

Carpenter --------------150----------------x hours
assistant -------------120---------------(x-2) hours

labor bill = cost of plumber + cost of assistant

150x+120(x-2)=2460

150x+120x-240=2460

270x=2700
/270
x= 10 hours ----------carpenter

assistant ---------8 hours