Can someone please help with this one small problem.....I confused myself.

Probability of an event E if the odds in favor of E are as shown below,

a)2 to 15

Thanks so much.

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- May 1st 2009, 08:25 PMambergarrett955Probability of an event
Can someone please help with this one small problem.....I confused myself.

Probability of an event E if the odds in favor of E are as shown below,

a)2 to 15

Thanks so much. - May 1st 2009, 10:06 PMGrandadOdds and probability
Hello ambergarrett955If the odds in favour of E are 2 to 15, then in the long run we can expect E to happen 2 times for every 15 times it doesn't happen. In other words, for every 17 trials we can expect E to occur 2 times.

So the probability of E is $\displaystyle \frac{2}{17}$.

If you want a formula, you can say that if the odds in favour of an event are $\displaystyle a$ to $\displaystyle b$, then the probability of the event is $\displaystyle \frac{a}{a+b}$.

Note also that if you're given the odds*against*something happening, you need to use the*second*number for the numerator of the fraction when you're working out the probability. For instance, if the odds are 10 to 1 against something happening, then the probability that it will happen is $\displaystyle \frac{1}{11}$, and the formula is:

If the odds*against*an event are $\displaystyle a$ to $\displaystyle b$, then the probability that the event occurs is $\displaystyle \frac{b}{a+b}$.

Grandad