All triangles should equal 180 so the answer is B. When you solve it you get 60, 60, 60 which equals 180
Answer:

Step-by-step explanation:
Since it is -1, put 1/something
Total students 5+16+42+22+5 = 90
0-1's probability is 5 / 90 = 5.5% about
2-3's probability is 16 / 90 = 17.7% about
4-5's probability is 42 / 60 = 46.6% about
6-7's probability is 22 / 90 = 24.4% about
8+'s probability is 5 / 90 = 5.5% about
(percentages not rounded, just cut off at the first decimal)
2+2+1 3/4+1 1/4+1+1=9 . Hope this helps :)