Question 505011
If 4 men can do the job in 9 days,how many men were needed to do the job in 12 days?
<pre>
Since 4 men can do the job in 9 days, then it would take 1 man 4 times as long or 36 days.

12 days is 3 times as fast as the 36 days it would take 1 man, so it will take
3 men.

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Or you can use the formula

W<sub>1</sub>*T<sub>1</sub>     W<sub>2</sub>*T<sub>2</sub> 
-----  =  -----   
 J<sub>1</sub>        J<sub>2</sub>

where 
W<sub>1</sub> = number of workers in the first ssituation = 4
T<sub>1</sub> = number of days in the first situation = 9
J<sub>1</sub> = number of jobs in the first situation = 1

W<sub>2</sub> = number of workers in the second ssituation = ?
T<sub>2</sub> = number of days in the second situation = 12
J<sub>2</sub> = number of jobs in the second situation = 1

4*9   W<sub>2</sub>*12
--- = -----
 1      1

 36 = 12W<sub>2</sub>

  3 = W<sub>2</sub> 

Edwin</pre>