<PRE><B>Question 1200641</B>
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3 men can unload 270 kg of goods in 4 hours. 
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r, rate for 1 man
{{{3r*4=270}}}


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How many men are needed to unload 540 kg of goods in 3 hours?
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r, rate for 1 man
n, number of men

{{{nr*3=540}}}


system to solve, for n  (since factor r will cancel)
{{{system(3*4*r=270,3rn=540)}}}


Eq.2 divided by Eq.1
{{{(3rn)/(3*4*r)=540/270}}}


{{{n/4=2}}}


{{{highlight(n=8)}}}

</PRE>