Name a key which is hardest to turn.

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

Find the mistake in the below maths equations

A = 2
A(A-1) = 2(A-1)
A2-A = 2A-2
A2-2A = A-2
A(A-2) = A-2
A = 1

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

I make two people out of one. What am I?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?