Answer:
It takes an apprentice four times as long as the experienced plumber to replace the pipes under an old house. It takes them 14 hours when they work together.
Step-by-step explanation:
5/(4x) = 1/14
x = 35/2
The plumber takes x = 35/2 hours to replace the pipes alone.
The apprentice takes 4x = 70 hours to replace the pipes alone.