Well, Veribus and ******, you're right

The correct answer is 4 and 13. Unfortunately I have no program to solve it, but proving it by hand is not that difficult in this case when you just have to pick one of four answers. Proving that there exists such a solution within ]1,100[ is something different, hmm, maybe I should really try to write a program. Tomorrow is public holiday in Germany so I have a lot of time

Or maybe I give this program as homework to my students
Think there are more "riddles" from this entrance test, if wanted I can post some
