Question 951200
<pre>
If the test has n questions, they can be arranged
in n! ways:


If the test has     they can be
  this many         arranged in
  questions,       this many ways
      1              1! = 1
      2              2! = 2
      3              3! = 6
      4              4! = 24
      5              5! = 120   <-- not quite enough 
      6              6! = 720   <-- more than enough

So the test must have 6 questions.

Edwin</pre>