Fifty part-time students were asked how many courses they were taking this term. The incomplete) results are shown below. Part (b)
What percent of students take exactly two courses?
Part (c)
What percent of students take one or two courses?
%

20% of students take exactly two courses, and 50% of students take one or two courses.

Given that fifty part-time students were asked how many courses they were taking this term, of which 15 take only 1 course, while 10 take 2 courses, to determine what percent of students take exactly two courses, and what percent of students take one or two courses, the following calculation must be performed:

Therefore, 20% of students take exactly two courses, and 50% of students take one or two courses.

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There are 50 part-time students:

15 of them, take only one course.

10 of them, take only two courses.

then the rest, this is:

50 - 10 - 15 = 25

25 students take 3 courses.

b) What percent of students take exactly two courses?

15 out of 50 take exactly two courses, the percentage is:

p = (10/50)*100% = 20%.

c) What percent of students take one or two courses?

This will be the percentage of students that take only one course plus the percentage of students that take two courses:

The percentage of students that take two courses is already known: 20%.

Now, for 1 course we have 15 students out of 50, the percentage is:

p = (15/50)*100% = 30%.

Then the percentage that take 1 or 2 courses is:

P = 30% + 20% = 50%