Counting and probability puzzles

Casework, complementary counting, and probability with combinations.

Standards:AMC 8AMC 10

Try it: three questions

Real questions from the practice bank. Tap an answer to check it.

Question 1 of 3

A bag contains 5 red marbles, 3 blue marbles, and 2 green marbles. If you draw 2 marbles without replacement, what is the probability that both are red?

Question 2 of 3

A committee of 4 people is to be chosen from a group of 7 people. How many different committees are possible?

Question 3 of 3

A jar contains 5 red marbles, 3 blue marbles, and 2 green marbles. If you draw two marbles without replacement, what is the probability that both are red?

How this fits in

Counting and probability puzzles is one skill in the SAT / Olympiad Prep unit. Students read the unit lesson, then earn a bronze, silver, or gold medal on their last 10 answers. Medals never go down. A mastered unit comes back for review after 1, 3, 7, 16, and 35 days so it stays learned.

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