Sorry but every test ever made has results that fall somewhere inside a bell curve and anyone to the right of the midline has better than average results and the further fight that you go (the higher the score) the more above average you are, all the way to "excels".
A person with normal cognitive skills will answer all the questions on the Montreal assessment. It isn't timed. It isn't graded. If Trump, in fact, took the test then he either got the same results as a normal, fully-functioning person did or else he didn't.