Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

Can you count the number of quadrilaterals in the picture below?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

What kind of band never plays music?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

Kohli and Dhoni decided to have a paintball match.
Kohli told Dhoni, "Sir it is not right as you got thrice the paintballs I have".

Dhoni instantly gives Kohli 10 hit paintballs.
Kohli replied, "Sir, I believe you still have twice the paintballs than I have".

Dhoni gives "?" more paintballs to Kohli.
Kohli replied, "Sir it is even now, Let us have a match".

What is "?".

Can you find the key in the picture below?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?