Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

A large water tank has two inlet pipes (a large one and a small one) and one outlet pipe. It takes 3 hours to fill the tank with the large inlet pipe. On the other hand, it takes 6 hours to fill the tank with the small inlet pipe. The outlet pipe allows the full tank to be emptied in 9 hours.

What fraction of the tank (initially empty) will be filled in 0.64 hours if all three pipes are in operation? Give your answer to two decimal places (e.g., 0.25, 0.5, or 0.75).

You can see three almost identical images below. Can you spot the odd one out from them?

Why blonde cannot dial 911?

Can you find the company name in the pictogram below?

What is the next number in this matchsticks series riddle?

What building has the most stories?

Two Twins Jack and Jill were standing back to back and suddenly they started running in opposite direction for 4 kilometres and then turn to left and run for another 3 kilometres.

what is the distance between the Baggio twins when they stop ?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98