AUTOMATA EXAM 1

                             X
                             X
                             X
                       X     X
                       X     X
                 X     X     X
 number          X     X     X
of exams         X     X     X     X
                 X     X     X     X
                 X     X     X     X
                 X     X     X     X
                 X     X     X     X
     X     X     X     X     X     X
     X     X     X     X     X     X
    -----------------------------------
    0-50 51-60 61-70 71-80 81-90 91-100
                  grades

=======================================

AUTOMATA EXAM 2

                 X           X
                 X     X     X
                 X     X     X
 number          X     X     X
of exams         X     X     X
                 X     X     X     X
                 X     X     X     X
     X           X     X     X     X
     X           X     X     X     X
     X     X     X     X     X     X
     X     X     X     X     X     X
    -----------------------------------
    0-50 51-60 61-70 71-80 81-90 91-100
                  grades

=======================================

AUTOMATA EXAM 3

 number
of exams               X     
                 X     X     
     X     X     X     X     
     X     X     X     X     X
     X     X     X     X     X     
     X     X     X     X     X     
     X     X     X     X     X     
     X     X     X     X     X     
     X     X     X     X     X     X
     X     X     X     X     X     X
    -----------------------------------
    0-50 51-60 61-70 71-80 81-90 91-100
                  grades