Theres a light bulb in a room and outside the room there are three switches. One of the switches operates the light bulb and all three switches are on the off position. How can you determine which switch operates the light bulb if you are only allowed to enter the room once to see if the light bulb is on or not (the light is not visible from outside)?
- Magazine competitions - Issue 39 @ tvchoicemagazine.co.uk55
- Win 1 of 3 x £1000 Selfridges vouchers with Virgin Trains109
- Win a Free minion usb stick1010
- totalev.com comp - win an electric car2121