Question 397409
A plumber and his assistant work together to replace the pipes in an old house.
 The plumber charges $45 an hour for his own labor and $25 for his assistant on
 this job, and the labor charge on the final bill is $4025.
 How long did the plumber and his assistant work on this job?
:
Let t = time in hrs that both worked
:
45t + 25t = 4025