Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

If an electric train is travelling south, then which way is the smoke going?

John: "Hi Teacher, What is your favourite movie ?".
Chemistry Teacher: "Indium Cerium Platinum Iodine Oxygen Nitrogen".
Ten seconds later... John replied I got it.

Do you?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Find the missing number in the image below.

What word is pronounced the same if you take away four of its five letters?