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20 votes
20 votes
There are 2 green pens, 3 blue pens, 4 red pens, and 1 black pen in the teachers desk. The teacher selects 2 pens at random, and the pens are not replaced. What is the probability that the teachers will pick 2 red pens in a row?

User Joseangelmt
by
3.0k points

1 Answer

24 votes
24 votes

Answer:

2/15

Explanation:

2 green pens, 3 blue pens, 4 red pens, and 1 black pen =10 pens

P(red) = red/total = 4/10 = 2/5

Keep the pen

2 green pens, 3 blue pens, 3 red pens, and 1 black pen =9 pens

P(red) = red/total = 3/9 = 1/3

P(red,red) = 2/5 * 1/3 = 2/15

User Fabrice TIERCELIN
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3.0k points