If two people are selected at random, the probability that they do no have the same birthday (day n month) is 365/365 x 364/365. explain why this is so
2007-10-29 10:59:05 · 3 answers · asked by Mimi 2 in Science & Mathematics ➔ Mathematics
Probability is the ratio of the number of possibilities that are desired to the number of possibilities in total. In your question, the desired option is any day that is not the day of the first birthday. So, given any particular day of the year, there are 364 days that are not that day and 365 days total in the year. That makes the probability 364/365.
BTW, This formula, assumes that births occur randomly, and this is not the case. Tell your teacher this. It'll impress him/her. People are more likely to be born at certain times of the year than others, so this formula likely doesn't match the real chance. http://abcnews.go.com/Health/Science/story?id=990641
2007-10-29 11:10:28 · answer #1 · answered by icebox766 4 · 0⤊ 0⤋
The first date can be any day of the year, so it will occur1 time out of 1. The second birthday can be any of the other 364, so it is possible 364 out of 365 times. Note: You didn't include February 29, which occurs once every 4 years with only a few exceptions. If you were supposed to, it'll make a difference in your statistics.
2007-10-29 18:12:09 · answer #2 · answered by jelesais2000 7 · 0⤊ 0⤋
Since 365/365=1, it's just 364/365. Just think about randomly giving the first person a birthday, and then bringing in a second person. There's only one day in 365 the second person could be born that's the same as the first person.
2007-10-29 18:02:55 · answer #3 · answered by JP 3 · 0⤊ 0⤋