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

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

O T T F F S S ?

What is the centre of gravity?

A landlord calls both of his sons and tells them that their horses will now decide who will transfer the inheritance. He tells them to race along the land till the end and the one whose horse will be slower will win and be the heir to all the property.

Both of them keep wandering for days but to no result. Then they ask a wise man regarding it. The man advises them on the matter after which they jump on the horses and race as fast as they can till the end. Why did they do it?

What did the wise man say?

What seven-letter word has hundreds of letters in it?

On a magical land of Mexico , all the animal in the land are rational.

There are 10 tigers and one goat.
Tiger can eat goat but since it's a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

How many triangles do you see in the picture puzzle below?

I taste better than I can smell. Who am I?

Count the squares in the matchstick puzzle below?

No matter how little or how much you use me, you change me every month. What am I?