Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

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

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

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?

Jim and Sarah are in a long-distance relationship. Jim buys an engagement ring for Sarah and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Jim has locks and Sarah has locks, but neither has keys for each other’s locks. How can they make sure the ring isn’t stolen?

Find the last number in the series below:

voN luJ yaM raM ---

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

I am soft and cuddly that soothe your heart. But, If you pick my last name I am going to tear you all apart. Who am I?