Question

Nick O’ Time, the plumber, charges $30 per hour. His brother Ivan, the plumber’s helper, charges $20 per hour. Nick starts working on a job. Four hours later Ivan joins him and both work until the job is finished. If they make a total of $470, how long did they work together?

Answer 1

Answer:

7 hours

They worked together for 7 hours ($350 + $120)