It takes 16 minutes for 9 people to paint 8 walls.

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

9 people take 16 minutes to paint 8 walls.

Let us first find how long it would take 4 people to paint the same 8 walls.

9 people did the job in 16 minutes.

1 person would do it in (9 * 16)

4 people would take (9*16) / 4 = 9*4 = 36 minutes.

So 4 people would do the same job of painting 8 walls in 36 minutes.

So now let us find how long it would take to paint 6 walls.

8 walls was painted in 36 minutes.

1 wall would take 36/8

4 walls would then take: 36 / 8 * 4 = 18

= 18 minutes.

Therefore 4 people would paint 6 walls in 18 minutes working at the same rate.

Hope this explains it.