All of the members of our spray-painting team paint at the same speed. If $8$ team members can paint a certain wall in $36$ minutes, then how many minutes would it take $18$ of our team members to paint the same wall?
It would take 18*8/36 = 4 minutes for 18 team members.
1 wall/ (36 min * 8 t) / 1 w / 18t = .0625 / min = 16 min