We know that the time it takes is directly proportional to the length of the wall but inversely proportional to the number of people working. That is [tex]t=k\cdot \frac{w}{p}[/tex]
We solve for the constant of proportionality, k. [tex]k=\frac{t\cdot p}{w}[/tex]
The initial values for k are the same for the final values. That is [tex]\frac{t_1\cdot p_1}{w_1}=\frac{t_2\cdot p_2}{w_2}[/tex]
