You are given eight coins and told that one of them is counterfeit. The counterfeit one is slightly heavier than the other seven. Otherwise, the coins look identical. Using a simple balance scale, how can you determine which coin is counterfeit using the scale only twice?
First weigh three coins against three others. If the weights are equal, weigh the remaining two against each other. The heavier one is the counterfeit. If one of the groups of three is heavier, weigh two of those coins against each other. If one is heavier, it’s the counterfeit. If they’re equal weight, the third coin is the counterfeit.
1020. There are 6 men with 2 legs each, for a total of 12 legs. There are 36 cats with 4 legs each for a total of 144 legs. There are 216 kittens with 4 legs each for a total of 864 legs 12 + 144 + 864 = 1020.
It cannot be seen, it cannot be felt, Cannot be heard, cannot be smelt, Lies behind stars and under hills, And empty holes it fills. Comes first follows after, Ends life kills laughter.
I am the owner of a pet store. If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?
If you put one canary in each cage, you have an extra bird without a cage. However, if you put two canaries in each cage then you have two canaries in the first cage, two canaries in the second cage and an extra cage.