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A bag contains six green marbles and nine black marbles. A marble is selected and
returned to the bag. This process continues until a marble has been drawn 5 times.
What is the probability that
a) Four marbles are green?
b) Three marbles are black?
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In all, there are 6+9 = 15 marbles.
The probability to select a green marble is = = 0.4 at each single trial.
The probability to select a black marble is = = 0.6 at each single trial.
The problem is about a binomial distribution.
In case (a), the answer is P = = = 0.0768.
In case (b), the answer is P = = = 0.3456.
Solved.
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To see many other similar (and different) solved problems, look into the lessons
- Simple and simplest probability problems on Binomial distribution
- Typical binomial distribution probability problems
in this site.