Which tank will fill first?

I am an odd number. Take away a letter and I become even. What number am I?

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

Find the missing number in the image below.

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

What does it mean?

Why Wine Glass Stem is so long?

What four weights can be used to balance from 1 to 30 pounds?

In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?

Why are all black people so quick ?