Question about Probability

Question

around Halloween each year the grocery store sells 3-pound bags of candy containing a mixture of Snickers, Milky Way, and Twix. If the bag has an equal number for each bar, what are the probabilities of finding each of the following:

a. randomly selecting a Milky Way bar

b. randomly selecting either a Snickers or Twix bar

c. randomly selecting something other than a Twix bar

Answer 1

There are 3 different types of candies: Snickers, Milky Way, and Twix.

They have the equally likely outcome in this case since there is a same number of candies in each bag.

P(Snickers) = P(Milky Way) = P(Twix) = 1/3

a) P(Milky Way) = 1/3 = 0.3333

b) P(Snickers or Twix) = P(Snickers) + P(Twix) - P(Snickers and Twix)

= (1/3) + (1/3) - [(1/3)*(1/3)]

= (2/3) - (1/9) = (6/9) - (1/9) = 5/9 = 0.5556

c) P(Not Twix) = 1 - P(Twix) = 1 - (1/3) = 2/3 = 0.6667

The probability of selecting a Milky Way bar is 0.3333.

The probability of selecting either a Snickers or Twix bar is 0.5556.

The probability of selecting other than a Twix bar is 0.6667.