15 employers working 10 hours per day built a 180m long canal for 12 days. How many days need 32 employers working 8 hours per day to built a 600 m long canal?

  • $\begingroup$ Any thoughts? How many meters can one worker build in an hour? $\endgroup$ – lulu Feb 14 '17 at 12:44


  • How many hours to 15 employees need to dig the 180m canal?
  • Therefore, how many hours would just one employee need?
  • Therefore, how long a canal does one employee dig in one hour?
  • Therefore, how long a canal do 32 employees dig in one hour?
  • Therefore, how many hours do 32 employees need to dig 600m of canal?

Answer these questions one by one, tell me where you get stuck.

  • $\begingroup$ @Let'sGo Nicely done. Those are correct answers to questions 1 and 2. Keep going! $\endgroup$ – 5xum Feb 14 '17 at 12:53
  • $\begingroup$ 15 employees need 120 hours to dig the 180 m canal therefore one employee needs 1800 hours to dig a 180 m canal. so in one hour he can dig 1\10 meters therefore in one hour 32 employees can dig 3.2 meters so to dig a 600 meters canal they will need 187.5 hours.Am i right? $\endgroup$ – user415900 Feb 14 '17 at 12:59
  • $\begingroup$ @Let'sGo Looks good to me! $\endgroup$ – 5xum Feb 14 '17 at 13:01
  • $\begingroup$ but i have another result in my book its 23 and 7\16 days $\endgroup$ – user415900 Feb 14 '17 at 13:05
  • $\begingroup$ @Let'sGo Well yeah, if you work $187.5$ hours, and you work 8 hours each day, then how many days do you work? $\endgroup$ – 5xum Feb 14 '17 at 13:07

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