It takes 46 minutes for 10 people to paint 3 walls

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

It takes 46 minutes for 10 people to paint 3 walls

It takes 92 minutes for 10 people to paint 6 walls (twice as long because you have twice as many walls)

You only have 4 people to paint the walls instead of 10 people

Therefore it will take 2.5 times as long (10/4=2.5)

2.5*92=230 minutes