Why are manhole covers round?

Why is it better to have round manhole covers
than square ones?

Alphabet puzzle?

There are three words in the English language
that end in "gry". ONE is angry and the other
is hungry. EveryONE knows what the third ONE
means and what it stands for. EveryONE uses
them everyday, and if you listened very
carefully, I've given you the third word.
What is it? _______gry?

Horse Problem

There are 25 horses and 5 race tracks.
We have to pick the fastest three horses in the
least no of races. PS: In one race only 5 horses
can participate. Find the least number of races?

Microsofts Puzzle

You have 5 jars of pills. Each pill weighs
10 gram, except for contaminated pills contained
in one jar, where each pill weighs 9 gm. Given
a scale, how could you tell which jar had the
contaminated pills in just one measurement?