Question

It takes 636363 minutes for 444 people to paint 999 walls. how many minutes does it take 777 people to paint 444 walls? minutes

Answer 1

Let t=time, p=people, and w=walls.

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 
     $t=k\cdot \frac{w}{p}$

We solve for the constant of proportionality, k.
     $k=\frac{t\cdot p}{w}$

The initial values for k are the same for the final values. That is
     $\frac{t_1\cdot p_1}{w_1}=\frac{t_2\cdot p_2}{w_2}$

     $\frac{63\cdot 4}{9}=\frac{t_2\cdot 7}{4}$

     $t_2=\frac{4\cdot 63\cdot 4}{7\cdot 9}=16$

It will take 16 minutes.