After an exam, the scores of students in a class are summarized as follows:

Range of score	Number of students
0-49	3
50-59	6
60-69	12
70-79	20
80-89	15
90-100	5

1.

A student passes the exam only if their score is at least 60. Based on the data provided, what is the probability that a randomly chosen student passes the exam?

a)85.2%

b)81.2%

c)91.4%

d)89.5%

2.

A student with a score between 70 and 89 is awarded the letter grade "B". Based on the data provided, what is the probability that a randomly chosen student obtains a grade of "B"?

a)59.3%

b)57.4%

c)52.9%

d)61.3%