1. Suppose that the weather each day is unrelated to any other day, and it can be simply described as a cloudy day or a clear day. Given that the probability of a cloudy day in a certain city is 0.56.
What is the probability that two clear days are in consecutive?
The answer is 0.1936.
2. Two people A and B shoot at a target simultaneously and the probabilities that they hit the target are 1/3 and 1/4 respectively. Find the probability of each of the following events.
Only one of them hits the target.
The answer is 5 / 12.
3. Jacky is practicing his soccer penalty shots. He needs to shoot until he scores. Assume that every attempt made by him is not affected by his previous one, and the probability of him scoring in penalty shots is 0.8, find the probability of each of the following events.
(a) He scores in his first shot.
(b) He does not score until his third shot.
The answers are (a) 0.8, (b) 0.032.
關於probability的簡單Maths.問題
2009-10-03 7:23 am
回答 (1)
2009-10-03 11:05 am
✔ 最佳答案
1)P( two clear days are in consecutive)= (1 - 0.56)^2 = 0.44^2 = 0.1936
2)P(only one of them hit the target)
=P(A hit and B not hit) + P(A not hit but B hit)
= (1/3)(1 - 1/4) + (1 - 1/3)(1/4)
= 1/3 * 3/4 + 2/3 * 1/4
= 1/4 + 1/6
= 5/12
3a) P(He scores in his first shot.)
= P( He scores in penalty shots )
= 0.8
b) (1 - 0.8)(1 - 0.8)(0.8)
= 0.032
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