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The top three winners of the local origami folding contest are Ashley, Beatrice, and Christopher. Veteran origamian Ashley can fold 100 paper cranes in 5 minutes. New-comers Beatrice and Christopher can both fold 100 cranes in 6 minutes.Together they will represent their school at the State contest. They will work as a team to compete in the event where they have to fold 480 paper cranes in the least amount of time. Assuming their speed of folding paper cranes does not change at all. How long does it take?

 Jan 9, 2021
 #1
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Together they fold   100/5  + 100/6 = (600+500)/30 = 1100/30    cranes per minute

 

480 cranes / (1100/30 cranes / minute) = 480 * 30 /1100 = ~ 13  minutes

 Jan 9, 2021
 #3
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Yep, Chris is right ....Guest didn't account for TWO people folding at 100/6 rate:

Together they fold   100/5  + 100/6 + 100/6  = (600+500 +500)/30 = 1600/30    cranes per minute

 

480 cranes / (1600/30 cranes / minute) = 480 * 30 /1600 =9 minutes

Guest Jan 9, 2021
 #2
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Ashley  can  fold   100/5  = 20  per minute

 

Beatrice and Christopher can fold    100/6  = 50/3  cranes per minute

 

So

 

Total Work  / Rate  =  Total Time

 

        480                            480                               480 * 3

_______________  =  _________________  = _________  =   3*3   =    9 minutes

20 + 50/3 + 50/3             (60 + 50 + 50) / 3              160   

 

 

cool cool cool    

 Jan 9, 2021
 #4
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thank you :)

 Jan 9, 2021

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