In the initial exam key the correct answer was specified as C for question #50. After the initial grading was done we realized that choices A, B, and C were all correct answers for this question.

So we decided to drop question #50 from the exam.

Whether your exam 2 grade went up or down can be understood as follows:

1. Say you did not mark C on question #50, then that was initially scored wrong and your score was calculated as [(number correct answers)/50] = decimal% and your points were decimal%*150. Under this scenario, when question #50 was eliminated, your new grade became [(number initial correct answers+1)/49] = decimal% and your points were decimal%*150. The +1 comes into play because question #50 was initially scored as wrong in this case. How much your score went up is dependent on how many questions of the remaining 49 were answered correctly.

2. Say you did mark C on question #50, then that was initially scored correct and your score was calculated as [(number correct answers)/50] = decimal% and your points were decimal%*150. Under this scenario, when question #50 was eliminated, your new grade became [(number initial correct answers-1)/49] = decimal% and your points were decimal%*150. The -1 comes into play because question #50 was initially scored as correct in this case. How much your score went down is dependent on how many questions of the remaining 49 were answered correctly.

That's the math behind the adjustments that occurred when question #50 was dropped from the exam. This was the only completely fair way to correct the mistake. In reality, the exams were re-graded by computer using a 49 question key and these changes occurred automatically in the new scores.

Hope this helps you understand what happened in your case. If it is still not clear, drop by and we can talk about it some more.