12-1: Mutually Exclusive events and Addition Rule

There are 12 red roses, 5 yellow roses and 3 white roses in a vase. Felix takes a rose, at random, from the vase.

What is the probability of him choosing a red or a white rose?

Answer explanation

P(red or white) = P(red) + P(white) 12/20 + 3/20 = 15/20 reduce the fraction to 3/4

There are 20 roses in a vase. 12 are red roses, 5 are yellow roses and 3 are white roses. Felix takes a rose, at random, from the vase.

What is the probability of him choosing a yellow rose or a white one?

Answer explanation

There are 5 yellow roses and 3 white ones. Add 5/20 + 3/20 = 8/20 = 2/5

In a landfill, there is a 27% chance that a piece of trash is recyclable plastic, a 54% chance that the item is biodegradable, and a 9% chance that the item is neither of these things. Pick of piece of trash at random. What is the probability that it is recyclable plastic or biodegradable?

• 81%

• 21%

• 54%

• 63%

In a pet store, there are 6 puppies, 4 kittens, and 7 parakeets. If a pet is chosen at random, what is the probability of choosing a puppy or a parakeet?

• 11/17

• 13/17

• 10/17

• None of the above

The table show goals made by a soccer team along with the probability of each number occurring during a game. What is the probability that the team scores 3 or 4 goals?

• 0.11

• 0.46

• 0.13

• 0.31

If you roll one die, what is the probability of getting an odd number or a 4?

• 2/3
• 1/3
• 1/2
• 1/6

If a spinner is numbered 1 – 8, when you spin it the events of spinning an even number and a number less than 4 are

Look at the picture to visualize)

• Mutually Exclusive

• Not Mutually Exclusive

Danny has 20 total chocolates: 5 are milk chocolates, 10 are dark chocolates, and 5 are white chocolates.

What is the probability of getting a milk chocolate or a dark chocolate?

• 3/4

• 1/2

• 1/15

• 3/10

Edith plants a daffodil bulb. The probability that the bulb will grow is 0.8.

What is the probability that the bulb will not grow?

• 0.8

• 0.2

• 0.4

• 0.6

A bag contains 9 green marbles, 5 yellow marbles and 6 red marbles.  You choose one marble.   What is the probability of selecting a green or red marble?

• 8/15
• 6/11
• 3/4
• 2/3