During which month do people sleep the least?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

I have no life, but I can die. What am I?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?