exam 2	exam 1 + exam2
percentile	score	combined score
100%	13	26
90%	12	22
80%	10	20
70%	9	19.8
60%	8	18
50%	8	17
40%	7	15
30%	7	15
20%	6	12.8
10%	5	11
0%	0	4