What is next number in the pattern below:

131 517 192 123 ?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

What does this mean?

CCCCCCC

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

What English word has three consecutive double letters?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?