Probability from a sample space
Determine simple, complement, and compound probabilities from a described sample space, as a reduced fraction. Unlimited questions, five difficulty levels, and a full worked solution every time, included free with weekly lessons.
Try one
A bag has 7 red marbles, 8 blue marbles, and 5 green marbles. You draw one marble at random. What is the probability it is red? Give your answer as a fraction in lowest terms.
Answer: 7/20
See one solved, step by step
A bag has 5 red marbles, 5 blue marbles, and 3 green marbles. You draw one marble at random. What is the probability it is NOT blue? Give your answer as a fraction in lowest terms.
📘 Worked solution
1Total marbles: 5 + 5 + 3 = 13The total is every marble that could be drawn.
2Marbles that are NOT blue: 13 - 5 = 8The complement counts every outcome except blue.
3P = 813 = 813Probability is favourable outcomes over total outcomes, reduced to lowest terms.
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