Only one trip to the lamp room is required to match each lamp with its switch. Here is how to do it: • In the switch room turn on two lamps. • After a few minutes, turn off one of these. • Then go to the lamp room. • The lamp that is on matches the switch you left on. • The lamp that is off but has a warm bulb, matches the switch you turned on then off • The remaining lamp matches the

remaining switch.

What will be an ideal response?

Man #1 and 2 cross together (takes 2 minutes).
Man #1 goes back alone (takes 1 more minute). Man #3 and 4 cross together (takes 10 minutes). Man #2 takes flashlight back (takes 2 minutes).
Man #1 and 2 cross together again (takes 2 minutes).
Now all four have crossed and it took 2+1+10+2+2 = 17 minutes!

the two fastest men do the shuttling of the flashlight.