SOLUTION: 28 men can complete a piece of work in 21 days. How many more men must be hired to complete the work in 14 days?

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Question 884801: 28 men can complete a piece of work in 21 days. How many more men must be hired to complete the work in 14 days?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Either situation is for 1 job.
r = the rate for one man.
28r%2A21=1 and for some unknown number m of additional men, %2828%2Bm%29r%2A14=1. These both are for 1 job and the two left members are equal.

28r%2A21=%2828%2Bm%29r%2A14
%281%2F14r%29%2828%2A21r%29=%281%2F14r%29%2828%2Bm%2914r
42=28%2Bm
m=42-28
highlight%28m=14%29
Fourteen more men.