Simple Probability & Complement

Front

What is probability?

Back

Probability is a measure of the likelihood that an event will occur, expressed as a number between 0 and 1.

Front

What is the complement of an event?

Back

The complement of an event A is the event that A does not occur, denoted as A'. The probability of the complement is P(A') = 1 - P(A).

Front

How do you calculate the probability of an event?

Back

Probability of an event = (Number of favorable outcomes) / (Total number of outcomes).

Front

If a box has 6 red pens, 8 black pens, 2 blue pens, and 4 purple pens, what is the total number of pens?

Back

Total number of pens = 6 + 8 + 2 + 4 = 20 pens.

Front

What is P(red or blue) if a box has 6 red pens, 8 black pens, 2 blue pens, and 4 purple pens?

Back

P(red or blue) = (Number of red + Number of blue) / Total = (6 + 2) / 20 = 2/5.

Front

What is P(NOT red or blue) if a box has 6 red pens, 8 black pens, 2 blue pens, and 4 purple pens?

Back

P(NOT red or blue) = 1 - P(red or blue) = 1 - 2/5 = 3/5.

Front

If a bag of candy contains 2 red, 4 yellow, and 4 green candies, what is P(NOT red or yellow)?

Back

P(NOT red or yellow) = (Number of green) / Total = 4 / (2 + 4 + 4) = 4/10 = 2/5.

Front

What is the probability of drawing an even number from a set of numbers 1 to 7?

Back

Even numbers are 2, 4, 6. P(even) = Number of even numbers / Total numbers = 3/7.

Front

How do you find the probability of multiple events occurring?

Back

For independent events, P(A and B) = P(A) * P(B). For mutually exclusive events, P(A or B) = P(A) + P(B).

Front

What is the probability of drawing a blue pen from a box with 6 red, 8 black, 2 blue, and 4 purple pens?

Back

P(blue) = Number of blue pens / Total pens = 2 / 20 = 1/10.