I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

Can you count the number of lines in the below picture?

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

What four weights can be used to balance from 1 to 30 pounds?

John has played 50 ODI's and his average is 50. How many runs should he score in his 51st ODI, so that his average score jumps to 51?

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

What begins with T, ends with T, and has T in it?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?