Answer: Probability That Mail Will Arrive Before Noon at Least One Day Wed/Thurs

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Homework Help Overview

The discussion revolves around calculating the probability that mail will arrive before noon at least one day between Wednesday and Thursday, given specific probabilities for each day and the assumption of independence.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the concept of independent probabilities and consider the method of calculating the probability of at least one event occurring by examining the complementary probability of neither event occurring.

Discussion Status

Participants are actively engaging with the problem, questioning assumptions about the calculations, and discussing the implications of their findings. Some guidance has been offered regarding the approach to "at least one" probability problems.

Contextual Notes

There is uncertainty regarding the variable used in the calculations, and participants are considering how to properly combine the probabilities without exceeding one.

EvilPony
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There is a 80% chance that Wednesday's mail will be delivered before noon on Wednesday and a 40% chance that Thursday's mail will be delivered before noon on Thursday. If these probabilities are independent, what is the probability that the mail will arrive before noon at least one of those two days?
 
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What thoughts have you had so far?
 
heh guess I should be posting what I've done on these instead of just posting the question :)

ok well all I know is that its .8 (x) + .4 (x) , but I have no idea what the variable x is. I can't just add .8 and .4 because that would be greater then one. So i guess I just need help figuring out what x is
 
Well, why do you think that?
 
or maybe this has something to do with the independent test...
 
One way to go about solving "at least one" problems, is to think of the probability that none happen.
 
so 1-.2(.6)? which is 88% then?
 
Evilpony,

Does that answer (88%) seem to make sense? Should it be greater than the probability on either individual day?
 

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