Which Number is the odd one out?

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

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

Can you place three balls such that the equation shown in the picture holds true?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

If 21x = 79x, what is the value of x?

Can you find the mistake in the below statement?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?