I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

Replace the question mark with the number below given a simple math problem.

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

In a kingdom, King George did not allow any citizen to visit the world outside. Also, only a person with proper paperwork was allowed to enter or he was sent back. A wooden bridge was what connected the kingdom to the world. The king had appointed a sharpshooter who would check the every five minutes on the bridge to check. After checking, he would go back to his hut and return exactly after five minutes again. The bridge took 9 minutes to cross.

A merchant was able to escape the kingdom without harming the shooter. How?

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

The answer I give is yes, but what I mean is no. What was the question?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

If two's company, and three's a crowd, then whats four and five ?