SOLUTION: sammy can mow a lawn in 3 hours. his two young brothers can each do the job in 2 hours. if sammy and his two young brothers work together, how long would it take them to mow the la

Algebra ->  Rate-of-work-word-problems -> SOLUTION: sammy can mow a lawn in 3 hours. his two young brothers can each do the job in 2 hours. if sammy and his two young brothers work together, how long would it take them to mow the la      Log On


   

Question 526779: sammy can mow a lawn in 3 hours. his two young brothers can each do the job in 2 hours. if sammy and his two young brothers work together, how long would it take them to mow the lawn?
Found 2 solutions by alma11, Alan3354:
Answer by alma11(1) About Me  (Show Source):
You can put this solution on YOUR website!
Sammy 3
1 brother 2
2 brother 2
3-2=1
together in 1 hour

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
sammy can mow a lawn in 3 hours. his two young brothers can each do the job in 2 hours. if sammy and his two young brothers work together, how long would it take them to mow the lawn?
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Sammy does 1/3 per hour
Each brother does 1/2 per hour
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Together, they do 1/3 + 1/2 + 1/2 per hour = 4/3 per hour
4/3 lawn/hr --> 3/4 hour/lawn
--> 45 minutes