an instructor is evaluating the performance of students. he records the number of points that each student missed and created a frequency...

an instructor is evaluating the performance of students. he records the number of points that each student missed and created a frequency distribution. this is provided below

points missednumber of students

0 - under 102

10 - under 204

20 - under 3010

30 - under 408

40 - under 506

what is the mean number of points missed ?

a)20 b)29 c)30 d)35