Some please help it urgent

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

The area of a circle is equal to 1 dm². find the radius of the circle.

If we pull out the middle player of team a and the fourth player of the team b. what will be the force of team a and team b? what is their sum of forces