In the basement there are 3 light switches in the off position. Each switch controls 1 of 3 light bulbs on the floor above. You may move any of the switches, but you may only go up stairs one time. How can you determine which switch controls each light?
turn one switch on for a short time, turn the next one on for a longer period, and don't touch the 3rd one. Go upstairs and feel the bulbs. The warm one is switch #1, the hot bulb is switch #2 and the cold one is switch # 3.
Good answer Capt. very close to the official answer. Turn any one switch to the "on" position for 5 minutes, then turn that switch "off". Quickly turn any other switch to the "on" position and run up stairs. Feel the two lights that are "off". One of them will be "hot" because is was "on" for 5 minutes. Obviously the "hot" bulb is controlled by the first switch you turned "on". The light that is currently "on" is controlled by the switch you last turn "on". The "cold" bulb that is "off" is controlled by the only switch left. When solving problems we often need to use all our senses.
The 9 numbers in the list when totalled add up to 45, 4+5=9, also other than the #9 which obviously stands alone, the other numbers can be paired up so each pair equals 9.
Good answer Elieen, But there's more, It contains the numbers one to nine, in alphabetical order. Tom
