Question 972999
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I already did this one:  Question 972997


12 can do the job in 5 days.


12 can do 1/5 of the job in 1 day.


1 can do 1/5 times 1/12 or 1/60 of the job in 1 day


1 can do 3 times 1/60 or 1/20 of the job in 3 days.


So 20 can do the whole job in 3 days.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it