How many minutes does it take for 6 people to paint 4 walls?

Question

It takes 45 minutes for 4 people to paint 5 walls.

Answer 1

Since the time to paint walls is proportional to the number of walls (W) and inversely proportional to the number of people (P), then

Time = kW/P where k is the proportionality constant

In the first case,

Time = k(5)/4 = 45 minutes So, k = 36

So, in the second case,

Time = 36(4)/6 = 24 minutes