There were total 2000 people in the survey.
We can multiply relative frequency of any particular category with the total number of people to find the answer for each part.
<u>Part A: How many males surveyed preferred playing sports?
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Total Relative frequencies of Males who preferred playing sports = 0.30
Number of Males preferred playing sports = 0.30 x 2000 = 600.
<u>Part B: How many people surveyed preferred to read a book?
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Total Relative frequencies of people who preferred reading book = 0.10 + 0.15 = 0.25
Number of people preferred reading book = 0.25 x 2000 = 500.
<u>Part C: How many females were surveyed?
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Total Relative frequencies of Females = 0.15 + 0.05 + 0.15 = 0.35
Number of Females surveyed = 0.35 x 2000 = 700.