If eleven plus two equals one, what does nine plus five equal?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

Can you find out a way through which you can make five squares out of the given figure by moving just six match sticks?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

How many Watermelons are there in the below picture?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

Find the missing letter in the last circle logically in the given below picture.