What is next number in the pattern below:

131 517 192 123 ?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

What is both possible and impossible at the same time?

What has 88 keys?

If eleven plus two equals one, what does nine plus five equal?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

The more of this there is, the less you see. What is it?