The question:
The student John has 10 different pairs of shoes. He randomly takes 3 shoes.
1) Calculate how many possibilities does John have.
2) Calculate the probability that from the 3 taken shoes, 2 shoes are from the same pair.
So the first one is easy, it's (20*19*18)/3! = 1140, but I can't figure out the second one. According to the teacher, the answer is 15/38 but I have a feeling that it might be wrong.
The student John has 10 different pairs of shoes. He randomly takes 3 shoes.
1) Calculate how many possibilities does John have.
2) Calculate the probability that from the 3 taken shoes, 2 shoes are from the same pair.
So the first one is easy, it's (20*19*18)/3! = 1140, but I can't figure out the second one. According to the teacher, the answer is 15/38 but I have a feeling that it might be wrong.