if you have 8 balls, of which one weighs slightly more than the others, and you have a balance. how can you find out which one is heavier using only 2 weighings?
Solution :
First Step is to take 6 balls out of these 8 balls and measure these 6 balls with a set of 3 each on the weighing machine. There are only two possibilities that arises :
1) The balance is neutral, that means the heavy ball is in the two balls that are left. It is now easy to measure the remaining two ball on the balance and check which one is heavy. 2) The other possibility is that the heavy ball is among those 6 balls, the balance of one side will go down showing that there is a heavy ball in those 3 balls, in the second measurement just measure any of the two balls and if the balance is neutral the heavy ball is the third ball or if the balance deflects that shows that the heavy ball is the one which side the balance deflected.
OK, theres another one.
If u have a cup of 5 quarts and another of 3 quarts with unlimited supply of water, how will you get exactly 4 quarts of water using those two cups supplied ?
Uhhhh... How?
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Fill the 5 quart one and pour it into the 3 quart one. You have 2 quarts left in the 5 quart container. Dump that into where ever you want the gallon and repeat.
The exact solution is like this :
Fill the 5 quart one and pour it into the 3 quart one. You have 2 quarts in the 5 quart container and throw away all the water from the 3 quart container. The 2 quarts water from the 5 quarts container, pour it into the 3 quarts container. You have 5 quarts container empty and 3 quarts container filled with 2 quarts of water. Fill 5 quarts container with 5 quarts of water and then pour water from 5 quarts to 3 quarts to fill the quarts container. Indirectly you are pouring 1 quart of water from the 5 quarts. So you have 4 quarts of water left in the 5 quarts container.
