Question 1156875
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Six men working at the same rate can weed a farm in 16 days.
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r, the rate for one man
For one job of "weed a farm", and 6 men doing this job,  {{{6r*16=1}}}.
Or,  {{{r=1/96}}}.



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After working for 4 days, 2 more men were hired. How long did they take to weed the farm?
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"They" meaning all 6+2=8 men together to finish the job.

{{{highlight_green(6(1/96)*4+8(1/96)*x=1)}}}

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{{{6*4+8x=96}}}

{{{8x=96-24}}}

{{{highlight(x=9)}}}--------------------- nine more days after hiring the two more men