Question

A box contains 500 envelopes, of which 75 contain $100 in cash, 150 contain $25, and 275 contain $10. An envelope may be purchased for $25. What is the sample space for the different amounts of money? Assign probabilities to the sample points and then find the probability that the first envelope purchased contains less than $100.

Question 2
Suppose that in a senior college class of 500 students it is found that 210 smoke, 258 drink alcoholic beverages, 216 eat between meals, 122 smoke and drink alcoholic beverages, 83 eat between meals and drink alcoholic beverages, 97 smoke and eat between meals, and 52 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.

Answer 1