Answer:
Explanation:
We have three switches 1, 2 and 3.
Firstly, switch on the first switch for like 2mins, then switch of the first switch and switch on the second switch, then rush immediately up stars, if the bulb is on,
Then it is between switch 1 and 2, so feel the bulb immediately, if the bulb is hot, it show that it was switch 1 due to the heat the but has emitted over the long period of time, but if it is still cold and just about to be getting warm, then it is the second switch.
Second case, if the bulb was off when you get upstairs, this shows that it, it is between switch 1 and 3.
Now, feel the bulb, it is hot then, it is switch 1 due to the heat . but if it is cold then it is switch 3 because none of the switch was able to power on the bulb