A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Decode this picture on T-Shirt and tell what it says ?

What is the word or phrase?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

A father's child, a mother's child, yet no one's son.

Who am I?

What common phrase is represented by the below lines

Easy going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Medium going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Tough going:
Weak, 'I can't do it, I'm staying!'
Tough, 'Let's get going.'

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

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

If Japan and Panama decided to merge into a single country, probably people will name it Japanama.

Can you think of two more such country's unions that could produce similar names like Japanama by overlapping their three letters?