SOLUTION: A mason can construct a retaining wall in 10 h. The mason's experienced apprentice can do the same job in 15 h. How long would it take the mason's novice apprentice to do the job i

Question 1041876: A mason can construct a retaining wall in 10 h. The mason's experienced apprentice can do the same job in 15 h. How long would it take the mason's novice apprentice to do the job if, working together, all three can complete the wall in 5 h?

Answer by jorel555(1290) (Show Source): You can put this solution on YOUR website!
The mason can do 1/10th a wall per hour. Similarly, his apprentice can do 1/15th a wall per hour. So:
1/10+1/15+1/n=1/5
3n+2n+30=6n
n=30
The mason's novice apprentice would take 30 hours to do the job alone. ☺☺☺☺
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