PUMaC 2008 · 组合（B 组） · 第 1 题
PUMaC 2008 — Combinatorics (Division B) — Problem 1
题目详情
- (2 points) Sarah buys 3 gumballs from a gumball machine that contains 10 orange, 6 green, and 9 yellow gumballs. What is the probability that the first gumball is orange, the second is green or yellow, and the third is also orange?
解析
- Sarah buys 3 gumballs from a gumball machine that contains 10 orange, 6 green, and 9 yellow gumballs. What is the probability that the first gumball is orange, the second is green or yellow, and the third is also orange? 9 ( ANS: . There is a 10 in 25 chance for the first part to work, a 15 in 24 chance for the second 92 one to work, and a 9 in 23 chance for the last one. CB: EK, TW, ACH)