Back to Apply the Addition Rule — Problem 1 · Task Set 24

Exercises: Apply the Addition Rule for the Probability of A or B

Work through each section in order. For "or" probabilities, decide first whether the events can both happen: if they can, subtract the overlap P(A and B); if they cannot, the overlap is 0 and you simply add. Convert counts to probabilities over a single sample space before applying the rule, and check that your answer is between 0 and 1. Write interpretations in complete sentences.

Grade 10·21 problems·~32 min·Common Core Math - HS Statistics and Probability·group·hss-cp-b-7

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Warm-Up: Union, Overlap, and the Right Rule

These problems review the ideas the Addition Rule is built on.

You are asked to find the probability of " $A$ or $B$ ." Which combining rule does the connective "or" point to?

The Addition Rule: add the probabilities, then subtract the overlap.

The Multiplication Rule: multiply the probabilities.

Subtract the smaller probability from the larger.

Divide one probability by the other.