What is at the end of a rainbow?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

Solve the following series:
AZ, GT, MN, __, YB

What is black when you buy it, red when you use it, and gray when you throw it away?

What goes through cities and fields, but never moves?

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

Before Mount Everest was discovered, what was the highest mountain in the world?

I don't get anymore wetter, no matter how much rain falls on me.

If you say my name, I will no longer exist. What am I?