What is the word or phrase?

What number when divided in half becomes zero?

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

What goes up but never comes down?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

John buys rice at Rs.60/kg from Britain and then sells them at Rs.5/kg in India. As a result of this, he becomes a millionaire. How come?

A cricket has 6 legs, a squirrel has 4 legs and a spider has 8 legs.

In a local zoo, it was found that the total number of legs is 612. Also, there are equal number of each of the above animals/insects.

Can you find out how many animals are there in the zoo?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?