All members of our painting team paint at the same rate. If $10$ members can paint a $100$ square foot wall in $10$ minutes, then how long would it take the $15$ members to paint a $100$ square foot wall, in minutes?
10 members: 1000 ft^2 wall: 10 min
5 members: 1000 ft^2 wall: 20 min
Half the workforce means double the time.
+1212 
