Question

At a grocery store, 40% of purchases include milk, 25% of purchases include cereal, and 15% of purchases include both milk and cereal.

What is the probability that a purchase does not include milk nor cereal (i.e., no cereal and no milk)?

Type in the answer, in decimal form.  

Answer 1

Solution:

Prob [Milk] = 0.40

Prob [Cereal] = 0.25

Prob [ Both Milk and Cereal ] = 0.15

Now, Prob [ Milk or Cereal ] = Prob [Milk] + Prob [Cereal] - Prob [ Both Milk and Cereal ]

Prob [ Milk or Cereal ] = 0.40 + 0.25 - 0.15

Prob [ Milk or Cereal ] = 0.50

so,

Probability that purchase does not include milk nor cereal is given by,

Prob [ Neither Milk Nor Cereal ] = 1 - Prob [ Milk or Cereal ]

Prob [ Neither Milk Nor Cereal ] = 1 - 0.50

Prob [ Neither Milk Nor Cereal ] = 0.50 (Answer)

Please rating the answer. Thank you!