Which probability formula?

A box contains 5 purple marbles, 3 green marbles and 2 orange marbles. Draws are made without replacement.P(both marbles are purple).

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∩B) = P(A)⋅P(B∣A)

• P(B|A)=P(A∩B)/P(A)

• 

A jar contains 4 white chips, 5 purple chips, and 1 black chip. Chips are selected randomly one at a time, and are not replaced.

P(white, then purple, then black)

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∩B) = P(A)⋅P(B∣A)

• 
• P(A∪B) = P(A)+P(B)

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∩B) = P(A)⋅P(B∣A)

• 
• P(A∪B) = P(A)+P(B)

Clara picks a marble at random, puts it back, and then picks another marble at random.

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∩B) = P(A)⋅P(B∣A)

• 
• P(A∪B) = P(A)+P(B)

Yasmine places 4 blue beads and seven red beads in bag. What is the probability she picks a blue bead, puts it to the side and selects another blue bead?

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∩B) = P(A)⋅P(B∣A)

• 
• P(A∪B) = P(A)+P(B)

A farm has 5 brown cows and 10 white cows. A fence is open and two cows escape. What is the probability that it will be a brown cow, then a white cow?

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∩B) = P(A)⋅P(B∣A)

• 
• P(A∪B) = P(A)+P(B)

You pick a marble from this bag.

What is the probability you will choose either a black or white marble?

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∪B)=P(A)+P(B)-P(A∩B)

• 
• P(A∪B) = P(A)+P(B)

What is the probability of spinning green or blue?

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∪B)=P(A)+P(B)-P(A∩B)

• 
• P(A∪B) = P(A)+P(B)

In a standard deck of 52 cards there are 13 diamonds and 13 hearts (red) and 13 spades and 13 clubs (black). Find the probability of choosing a card at random that is a spade OR a 7.

Which formula would you use to solve this problem?

• P(A∩B) = P(A)⋅P(B)

• P(A∪B)=P(A)+P(B)-P(A∩B)

• 
• P(A∪B) = P(A)+P(B)

If you draw one card from a standard deck, what is the probability of drawing a 5 or a diamond?

Which formula would you use to solve this problem?

• P(A∩B) = P(A) ⋅ P(B)

• P(A∪B)=P(A) + P(B) - P(A∩B)

• 
• P(A∪B) = P(A) + P(B)