A wheel is divided into 12 slices. 6 slices award a 10% discount, 3 slices award a 20% discount, 2 slices award a 40% discount, 1 slice awards a 100% discount

Question

A) What is the probability that a customer gets at least a 40% discount?

B) What is the probability that a customer does not get at least a 40% discount?

C) What is the probability that a customer gets a 10% or 20% discount?

D) What is the probability that two customers in a row get a 20% discount? 

 

If I could get an explanation on what steps to take for each part of the question, it would be much appreciated?

Thank you.

Answer 1

12 slices as follows:

    value        number

     10%           6

     20%           3

     40%           2

    100%          1

                   ------

  Total             12

 

Now, you must assume that the likelihood of getting each of the 12 slices is exactly the same.  If so, the definition of probability applies:

     Probability = (number of successful outcomes) / (number of possible outcomes)

 

A) What is the probability that a customer gets at least a 40% discount?

     "at least" means this value or greater

     P(≥40%) = (2+1)/12 = 3/12 = 1/4   or 25%

 

B) . . .    o.k., you're on a roll !!       

           [Note: a probability of 1, or 100%, means certainty.  Therefore,

          the probability of NOT something is just 1-P(something), or 100%-P(something).]