Suppose that in a senior college class of 500500 students, it is found that 179179 smoke, 228228 drink alcoholic beverages, 191191 eat between meals, 9999 smoke and drink alcoholic beverages, 5959 eat between meals and drink alcoholic beverages, 7272 smoke and eat between meals, and 3030 engage in all three of these bad health practices. If a member of this senior class is selected at random, find the probability that the student (a) smokes but does not drink alcoholic beverages; (b) eats between meals and drinks alcoholic beverages but does not smoke; (c) neither smokes nor eats between meals.
Accepted Solution
A:
Answer: a) 0.16, b) 0.058, and c) 0.856.Step-by-step explanation:Since we have given that Number of students = 500Number of students smoke = 179Number of students drink alcohol = 228Number of students eat between meals = 119Number of students eat between meals and drink alcohol = 59Number of students eat between meals and smoke = 72Number of students engage in all three = 30 a) Probability that the student smokes but does not drink alcohol is given by[tex]P(S-A)=P(S)-P(S\cap A)\\\\P(S-A)=\dfrac{179}{500}-\dfrac{99}{500}\\\\P(S-A)=\dfrac{179-99}{500}\\\\P(S-A)=\dfrac{80}{500}\\\\P(S-A)=0.16[/tex]b) eats between meals and drink alcohol but does not smoke.[tex]P((M\cap A)-S)=P(M\cap A)-P(M\cap S\cap A)\\\\P((M\cap A)-S)=\dfrac{59}{500}-\dfrac{30}{500}\\\\P((M\cap A)-S)=\dfrac{59-30}{500}\\\\P((M\cap A)-S)=\dfrac{29}{500}\\\\P((M\cap A)-S)=0.058[/tex]c) neither smokes nor eats between meals.[tex]P(S'\cap M')=1-P(S\cup M)\\\\P(S'\cap M')=1-\dfrac{72}{500}\\\\P(S'\cap M')=\dfrac{500-72}{500}\\\\P(S'\cap M')=\dfrac{428}{500}=0.856[/tex]Hence, a) 0.16, b) 0.058, and c) 0.856.