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The cleanup crew is picking up litter from the side of the road. if one crew member can clean up a mile of road in 45 minutes, and another crew member can clean up a mile of the road in 70 minutes, approximately how much time will it take the crew members to clean up a mile of the road if they work together?

 Mar 23, 2020
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Note that   the first guy  cleans  1/45  of the road in one minute

 

And  the second guy cleans 1/70  of the road in one minute

 

Add  these fractions

 

1/45  + 1/70   =

 

[70 + 45 ]                 115

________  =          _____

  45 * 70                  3150

 

Take the reciprocal of this fraction  =     

 

3150

____  ≈   27.39  min for both working together

 115

 

 

cool cool cool

 Mar 23, 2020

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