Which Number is the odd one out?

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

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

I am beautiful, up in the sky. I am magical, yet I cannot fly. To people I bring luck, and to some people, riches. The boy at my end does whatever he wishes. What am I?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

Why is a river so rich ?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?