Probability, Permutations, and Combinations

What is the probability of event A occurring?

• P(A) = number of times the favorable event occurs / total number of times any event will occur

• P(A) = total number of times any event will occur / number of times the favorable event occurs

• P(A) = number of times the favorable event occurs / number of times the unfavorable event occurs

• P(A) = number of times the unfavorable event occurs / total number of times any event will occur.

Fill in the blank: If two events are independent, then the probability of both occurring is: P(A and B) = _____.

• P(A) + P(B)

• P(A) × P(B)

• P(A) - P(B)

• P(A) / P(B)

What is the definition of a permutation?

• A permutation is the number of arrangements (order matters) of r items taken from a set of n distinct items.

• A permutation is the number of selections (order does not matter) of r items taken from a set of n distinct items.

• A permutation is the number of ways an event can occur.

• A permutation is the number of ways two events can occur independently.

Evaluate 8!.

• 40320

• 5040

• 720

• 120

Fill in the blank: A combination is given by the formula: n C r = _____.

• n! / (n-r)!

• n! / r!

• n! / (n-r)!r!

• n! / r!(n-r)!

What is the probability of rolling a 2 or less on a number cube?

• 1/6

• 1/3

• 1/2

• 2/3

How many different four-course meals can be selected from three salads, seven main dishes, four side dishes, and six desserts?

• 504

• 5040

• 720

• 120

Fill in the blank: The Fundamental Counting Principle states that if one event can occur in m ways and another event can occur in n ways, then the number of ways that both events can occur is _____.

• A) m + n

• B) m × n

• C) m - n

• D) m / n

What is the probability of heads coming up both times when a fair coin is flipped twice?

• 1/4

• 1/2

• 1/3

• 1/6

How many different committees of three people can be chosen to work on a project from a group of nine people?

• 84

• 56

• 36

• 28