Based on Ex1 (participation >93%) and 
         Qz1 (participation <64%) and 
noting that several students did not participate in Qz1, consider

  G= Qz1 (120) + Ex1 (307)  for a maximum of 427 points.

Boundaries are approximately fuzzy; you can easily be on one
or the other size. The semester is not over and things change.

If
427>=  G > 360      A
360>=  G > 250      B+ or B
250>=  G > 200      C+ or C
200>=  G            D or F

If you did not participate in Qz1 use a grade for Qz1
based on your Ex1 grade.