There are 3 red socks, 4 green socks and 3 blue socks.You choose 2 socks. The…
2017
There are 3 red socks, 4 green socks and 3 blue socks.You choose 2 socks. The probability that they are of the same colour is
- A.
1/5
- B.
7/30
- C.
1/4
- D.
4/15
Attempted by 63 students.
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Correct answer: D
Solution: Find the probability that the two chosen socks are of the same colour.
Total socks = 3 + 4 + 3 = 10. Total ways to choose 2 socks = C(10,2) = 45.
Ways to pick two red socks = C(3,2) = 3; two green socks = C(4,2) = 6; two blue socks = C(3,2) = 3. Total favourable = 3 + 6 + 3 = 12.
Probability = favourable / total = 12 / 45 = 4 / 15 after simplifying.
Therefore, the probability that the two socks are of the same colour is 4/15.