What has hands, but can’t clap?

If six children and two dogs were under an umbrella, how come none of them got wet?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

By moving just one matchstick, you need to make the below statement true. Can you do it?

Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

If 21x = 79x, what is the value of x?

What four weights can be used to balance from 1 to 30 pounds?