What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside. The man said, "Oh! I am really sorry, I thought this was my room." He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man. What made her suspicious of that man? He might have been genuinely mistaken.

Which is the rope you never skip with?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

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

Do you know what I am?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

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?