What is the coolest letter in the alphabet?

Alpha is Beta's sister.

Gamma is a Beta mother.

Delta is Gamma's father.

Tango is Delta's mother.

Then,

How is Alpha related to Delta?

The centre of the third figure is empty. What digit should fit inside?

What is the longest word in the dictionary?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

The barber of Town shaves all men living in the town. No man living in the town is allowed to shave himself. The barber lives in that town. Who then shaves the barber of the town?

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

Spot 5 differences in two Christmas tree below: