Problem 10 of 25sta-010
A bag holds 6 purple, 4 blue and 10 green marbles, all the same size. One marble is drawn at random. What is the probability that the marble is blue?
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Solution walkthrough1:33
- Every marble is equally likely, so probability the marbles we want over all the marbles.
- Count all the marbles in the bag: .
- of the marbles are blue, so the probability of blue is .
- Divide top and bottom by : . Blue is one of five equal groups of four.
- Traps: counts colors, is blue over the other , and is not blue.