What if instead of having to calculate something very precisely, you proposed a MQC instead ?

You can' estimate the answers of a QCM. It's either A, B, C or D.
If Mr P is really that much greater than Mr E, he'll get only right answers, whereas Mr E will lose points by lacking accuracy. You could even ask each one of them to make a test for the other one; as long as he's better, Mr P will always win :)