Answer:
48 minutes.
Explanation:
We have been given that it takes 48 minutes for 7 people to paint 7 walls. We are asked to find time taken by 20 people to paint 20 walls.
First of all, we will find time taken by one person to paint one wall as:






Since one person can paint one wall in 48 minutes, so 20 people will paint 20 walls in 48 minutes as well.