Sooooooo..at about 2am this morning, Lik asked me this question:
"You are given 8 balls of the same size. You are told one ball is lighter than the rest. Then you are given a weighing machine, of which you can only use twice. How do you determine which ball is the lighter one?"
Take a minute and try to come up with an answer..get your rusty brain to work.
C'mon at least try........................................pleaseeee
OK, so i had my maths exam today. Needless to say it was fucking hard and i stopped attempting it after a hour and 15 minutes. (got the multiple choice answer from my friend next to me so it wasn't that bad ( : ) So i had like 45 minutes to spare...which i used to try to solve the question...which i eventually did after a while ( : Well, i think i did...
I guess the hardest part of the question would the the ambiguity of the word 'weighing machine', i.e everyone would probably think of this:
instead of this:
With this weighing machine(scale), it is now tremendously easy to solve the question. Firstly pick any 6 balls and place 3 on each side of the scale. If one side is higher, that means that the lighter ball is on the higher side, where as if the scale is balanced, it means that the lighter ball is 1 of the 2 that you left out. Ok, if the lighter ball is in the pile that wasn't on the scale (the 2 balls that you left out), then place the 2 balls on the scale and the ball which is higher on the scale is the lighter one. However, if the lighter ball was in the pile of 3 that was higher during your first try, select 2 balls from that pile of 3, and place them on the scale. If one side of the scale is higher then the other, the lighter ball is on the higher side. On the other hand, if the scale is balanced again, the ball that you left out would be the lighter one. ( :
Make sense? Fuck i'm goooood.
Kpui, I want my prize.