Question 631704
<pre>
It takes 7 people 12 hours to complete a job. If they worked at the same rate,
how many people would it take to complete the job in 16 hours.

Use the job-worker-time formula, which is:

{{{(W[1]T[1])/J[1]}}}{{{""=""}}}{{{(W[2]T[2])/J[2]}}}

where

W<sub>1</sub> = the number of workers in the first situation.
T<sub>1</sub> = the number of time units (days in this case) in the first situation.
J<sub>1</sub> = the number of jobs in the first situation.

W<sub>2</sub> = the number of workers in the second situation.
T<sub>2</sub> = the number of time units (days in this case) in the second situation.
J<sub>2</sub> = the number of jobs in the second situation.

W<sub>1</sub> = 7            W<sub>2</sub> = the unknown quantity     
T<sub>1</sub> = 12            T<sub>2</sub> = 16 
J<sub>1</sub> = 1             J<sub>2</sub> = 1

[There was only 1 job, so the number of jobs in both situations is 1.



{{{(W[1]T[1])/J[1]}}}{{{""=""}}}{{{(W[2]T[2])/J[2]}}}

{{{(7*12)/1}}}{{{""=""}}}{{{(W[2]*16)/1}}}

      84 = 16W<sub>2</sub>
      
Divide both sides by 8

      {{{84/16}}} = W<sub>2</sub>

      {{{21/4}}} = W<sub>2</sub>

The answer would be {{{5&1/4}}} workers. But since it's not nice to
cut workers in fourths :), we have to use 6 workers. and get it
done in less than 16 hours.

Edwin</pre>