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.

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

A man is found dead in his bathroom naked with blood scattered all around him. The bathroom was locked from the inside and there is no trace of any struggle. There is nothing in the bathroom except his pant with the belt still around and his shirt. Also, the medic team can't find any incision in his body that may have been the reason behind so much blood loss.

The Police department is clueless regarding this murder mystery.
Can you?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

Take one out and scratch my head, I am now black but once was red. What am I?

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

In the picture given below, can you find out which digit will take place of the question mark?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3