A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

I make two people out of one. What am I?

Why 1729 is a magic number? Answer Logically.

What you cannot hold but it is yours?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

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?