Answer:
c. 33.0%
d. 14.5%
Explanation:
For answering questions about percentages in different categories or combinations of categories, it is convenient to find the totals of rows and columns in the table. These totals are shown in the attached.
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c.
Students who surf total 32+65 = 97. Of those, 32 also skateboard. The requested percentage is ...
32/97 × 100% ≈ 33.0% . . . . surfers who also skateboard
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d.
The total number of students is 166. Of those, the number who neither surf nor skateboard is 24. That percentage is ...
24/166 × 100% ≈ 14.5% . . . . students who don't surf or skateboard
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Additional comment
a. 97/166 ≈ 58.4% surf
b. 89/166 ≈ 53.6% do not skateboard
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This sort of table is called a "two-way table." One set of categories is represented in rows, another set is represented in columns. This table is filled with frequencies. Such tables can also display relative frequencies by dividing the entire table by the total of totals in the lower right corner.