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 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?

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 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?

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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