Can you find the odd number in the following?

2716, 4135, 5321 and 7145

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

I am sure no one can have two things for dinner. what are they?

Why do we preferably have round manhole covers and not square ones?

Rihana, Peeta, and Logan order a pizza for $10. Out of the three, Rihana and Peeta were quite hungry and ate 6 slices a piece, while Logan had just 2 slices.

Now, they want to split the cost among them fairly but due to the lack of change, they decide to round off the cost to the nearest possible dollar.

Can you find out the fairway which should be used to split the money?

What if the pizza was worth $11?

Find the value of "?" in the ball picture Riddle below:

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?

Replace the question mark with the number below given a simple math problem.

Count the number of triangles in the picture below:

A man is trapped in a room. The room has only two possible exits doors. Through the first door there is a room constructed from magnifying glass. The blazing hot sun instantly fries anything or anyone that enters. Through the second door there is a fire-breathing dragon. How does the man escape?