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* 10 = 15 * x
100 / 15 = x = 20 / 3 min = 6 + 2/3 min = 6 min 40 sec