Thursday, January 29, 2009

3. 10,000 screws


3.In a production line, 10,000 small screws are to be sorted into packs of 50 each. Manual counting would be too tedious. suggest ways to solve this.

Either a weighing scale or an electromagnet can be used to solve this problem.


First method useing the electromagnet:

Firstly, we must adjust the voltage (resistance) of the electromagnet such that the electromagnet would attract the 'right' amount of screws.

Although this is one method, there is still one disadvantage of using it.

It was stated that adjust the voltage until it is able to attract only 50 screws, but how is that possible?
(It should not be possible as it would either attract all the screws or none.)

It is true that using a magnet is an easier way, but the electromagnet would attract indefinate amount of screws, in the end, we still have to count it again.



The other method is using the weighing scale which I personally think is a better way.

Firstly, we would have to count 50 screws and weigh them. Record the it down. Estimate the number of screws or take a handful of it and place it on the weighing scale. Either take away screws or add screws until you get the previous weight of 50 screws.Continue doing so until all screws are used up.