It is always ahead of me yet I can never see it. What is it?

I have some blue and red sock in my drawer. I have a total of 4 socks. I pick 2 socks and the chance that I get a pair of red socks is 1/2.

What is the chance of picking a pair of blue socks?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

What goes through cities and fields, but never moves?

During which month do people sleep the least?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

What has hands, but can’t clap?

Find the smallest sentence with all the English alphabet.

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?