What is the most difficult question that you faced?

Tweet

The paradox is an email that I received a few days ago and try as I might I cannot solve it. This is how it goes: A lawyer teaches law to a poor student on the condition that the student will learn and pay him when he qualifies wins his first case. However when the student qualifies he takes up another profession. The lawyer sues him for his fees. on the grounds if he wins he is paid and if he loses he still gets paid as the student has won his first case. The student is not worried as if he loses he does not have to pay as he has lost his case and if he wins the case the judgement is that he need not pay