SOLUTION: Adam Danny and Fred wanted to mow their parents lawn. Adam, working alone, would need twelve hours. Danny could do it in six hours, but Fred would only need four hours.
How long w
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-> SOLUTION: Adam Danny and Fred wanted to mow their parents lawn. Adam, working alone, would need twelve hours. Danny could do it in six hours, but Fred would only need four hours.
How long w
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Question 1148098: Adam Danny and Fred wanted to mow their parents lawn. Adam, working alone, would need twelve hours. Danny could do it in six hours, but Fred would only need four hours.
How long would it take to finish the job if the three brothers joined forces, working together? Found 2 solutions by ikleyn, greenestamps:Answer by ikleyn(52747) (Show Source):
Adam makes of the job per hour.
Danny makes of the job per hour.
Fred makes of the job per hour.
Wirking together, the three make = = = of the job per hour.
Hence, they will complete the job in 2 hours working together.
As an alternative to the standard algebraic solution shown by the other tutor, using the fractions of the job each worker does in one hour, try this....
The least common multiple (LCM) of the times for the three workers is 12 hours.
Consider how many lawns each of the workers could mow in 12 hours:
Adam could mow 12/12 = 1 of the lawns
Danny could mow 12/6 = 2 of the lawns
Fred could mow 12/4 = 3 of the lawns
So in 12 hours the three workers could mow the lawn 6 times.
That means the time it would take them to mow the one lawn is 12/6 = 2 hours.
