So I have a math probablity question.
Lets say there is a pile of money that I can win. I get 15 random numbers assigned to me (i get no say in the matter) and then a number out of 100 is drawn at random. If I hit on that 15% chance I win the money.
Now lets say I get three shots. Get 15 random numbers, number gets drawn out of 100 if I win I win game stops, If i lose we do it again. Get 15 random numbers, number gets drawn out of 100 if I win I win if I lose we do it again. Get 15 random numbers, number gets drawn out of 100 if I win I win if I lose I lose.
So basically I have a 15% chance of winning three times.. what is my overall chances of winning the money?
In: 2
You have two ways of calculating this
1. You can try and calculate the probability that you win the first time *or* you lose the first and win the second *or* you lose the first two and win the third.
2. You can calculate the probability that you won’t win any of them, and subtract that from the whole. (do you see why this works?)
The first approach is complicated. It requires figuring out the probability of three different scenarios and working out how the hell to combine them.
The second approach is simple: You just need to work out the probability of a single scenario: something happening three times in a row (where *something* is “not winning”)
On each draw, there’s an 85% (i.e. 0.85) probability of not winning. To work out the probability you lose all three, you just take 0.85 × 0.85 × 0.85. That’s the probability that you lose all three, so the probability that you win at least one of them is 1 – (probability of losing all three)
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