What month of the year has 28 days?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

Before Mount Everest was discovered, what was the highest mountain in the world?

Find the next number in the series

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

Give it food and it will live; give it water and it will die.

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

How many times can you subtract the number 5 from 25?