Complete the following series. It.s very logical:

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

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

I add 5 to 9 and get 2. The answer is correct, so what am I?

I am something people love or hate. I change peoples appearances and thoughts. If a person takes care of them self I will go up even higher. To some people I will fool them. To others I am a mystery. Some people might want to try and hide me but I will show. No matter how hard people try I will Never go down. What am I?

A little girl goes to the store and buys one dozen eggs. As she is going home, all but three break. How many eggs are left unbroken?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?

Find the missing number in the image below.

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.