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Originally Posted by Alex's Trip
Probability: The likelyhood of an even happening represented with a number between 0 and 1.
The Dover children, Eileen and Ben, are away at college. They visit home on random weekends, Eileen with a probability of 0.2 and Ben with a Probablility of 0.25. What is the probability that both will visit.
The probability of them both visiting is the two probabilities multiplied. As in 1/5 X 1/4 = 1/20 = .05
There is a 5% chance that they will both visit.
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The Katz Brothers, Bob and Tom, are hiding in a cellar. If either one sneezes, they will reveal their hiding places and be found. Bob's probability of sneezing is 0.6 and Tom's probability is 0.7 What is the probability that at least one sneezes?
My teacher didn't fully explain why one method for this didn't work, so I may be leaving something out...
You need to find the probability of the opposite of at least one of them sneezing, meaning neither of them sneezing, then subtracting that from one in order to find the answer (finding one opposite and subtracting from 1 (essentially another oppoiste) brings you back to the original question).
So in this case, the chance of neither of them sneezing is .4 X .3 (since .6 and .7 is the chance of them sneezing, you subtract those from one to get the chance of them not sneezing). So the probability that neither of them will sneeze is .12. We take that number and subtract it from 1. The answer is .88 or 88%.
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Thanks... I had the first one correct then (although I didn't want to post my answer for fear of looking dumb in case I was wrong!
)
But I couldn't think of how to solve the second one. I tried something, but knew it was wrong because the result was too low and I knew it had to be more than 0.7... I've completely forgotten about most of that stuff, it's been too long.
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Originally Posted by Alex's Trip
Wasn't that fun?
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Eh, I dunno... I'm glad I don't have to deal with that stuff anymore. I never liked mathematics, although probability was the least annoying part of it for me. It's fun every now and then.