Here's a riddle for you:
If you ask the question to the 1, it'll answer: None of them.
If you ask the question to the 90 , it'll answer: 6
If you ask the question to 86, it'll answer All of them
966 and 972 would also answer: All of them
But if you ask the same question to 49, you might get an answer such as : 4
So, my question is, if you ask the question to 34, what would it answer?
Try to solve without the hint first. But if neccessary, here is a hint.
add " + "symbol right before the numbers that you are asking to, and see what it looks like.
Do not look for a pattern for numbers. Numbers do not generate series. They have other meanings if you apply the first hint. Such as: +1 , +90, +972 etc.
As Marius and Mae Culpa mentioned, the numbers represent country telephone codes.
1 - USA - None of them.
90 - Turkey - 6.
86 - China - All of them.
966 - Saudi Arabia - all of them.
972 - Israel - All of them.
49 - Germany - 4.
34 - Spain - ?
So, what kind of a question that we have to ask in order to get kind of responses. As you can see, israel, saudi arabia and china have all different answer from others, turkey germany and usa. So what would differ from these 3 from these 3.
My other hint to you is think about their languages-alphabet.