I can answer 2 of them quite quickly with pen and paper (compsci, physics) and one that I had to look up some definitions on wikipedia (maths) so I am certain there are people who can do more than 5.
The computer science one seems weirdly easy compared to the rest, it's multiple choice and it is very easy to get it by process of elimination even if you don't understand how to actually do the problem.
Yes, many can answer the compsci and physics problems. The math problem is abstract and more difficult, but solving those 3 and 2 others seems nearly superhuman.
The computer science one seems weirdly easy compared to the rest, it's multiple choice and it is very easy to get it by process of elimination even if you don't understand how to actually do the problem.