Sydneyrellah
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Bing can finish a job in 8 hours. Bong can do it in 5 hours. if Bing worked for 3 hours and then Bong was asked to help him finish it, how long will Bong have to work with Bing to finish the job?
Work/Time Problem
- Thread starter Sydneyrellah
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To follow up, there will be
[MATH]1-\frac{3}{8}=\frac{5}{8}[/MATH]
of the job left to do once Bing has worked for 3 of the 8 hours it takes him to complete it. Next, I would observe that in 40 hours Bing can complete 5 jobs while Bong can complete 8 jobs, and so working together they can complete 13 jobs in 40 hours, which means it will take them:
[MATH]\frac{40}{13}\cdot\frac{5}{8}=\frac{25}{13}[/MATH]
hours to complete the job working together.
[MATH]1-\frac{3}{8}=\frac{5}{8}[/MATH]
of the job left to do once Bing has worked for 3 of the 8 hours it takes him to complete it. Next, I would observe that in 40 hours Bing can complete 5 jobs while Bong can complete 8 jobs, and so working together they can complete 13 jobs in 40 hours, which means it will take them:
[MATH]\frac{40}{13}\cdot\frac{5}{8}=\frac{25}{13}[/MATH]
hours to complete the job working together.