Back to Understand conditional probability — Problem 2 · Task Set 20

Exercises: Understand the Conditional Probability of A Given B as P(A and B)/P(B)

Work through each section in order. Show your reasoning where indicated. For explanation problems, write in complete sentences. Express probabilities as fractions in lowest terms or as decimals where requested.

Grade 10·20 problems·~35 min·Common Core Math - HS Statistics and Probability·group·hss-cp-a-3
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Warm-Up: Probability Foundations

These problems review skills you already know.

1.

A bag has 10 marbles: 4 red, 3 blue, 3 green. You draw one and are told it is not green. To find P(RedNot Green)P(\text{Red} \mid \text{Not Green}), what is the size of the restricted sample space (the outcomes you now consider)?