Question

If the odds against Deborahs winning first prize in a chess tournament are 1 to 11 what is the probability of the event that she will win first prize

Answer 1

Answer: $\dfrac{11}{12}$

Step-by-step explanation:

Given

The odds against winning in a chess tournament are 1 to 11.

Odds is defined as the ratio of the probability of occurrence to the non-occurrence of event.

$\therefore \text{Probability that event will occur is P'=}\dfrac{1}{1+11}\\\\\Rightarrow P'=\dfrac{1}{12}$

Probability of non-occurrence i.e. she wins the first prize is

$\Rightarrow P=1-\dfrac{1}{12}\\\\\Rightarrow P=\dfrac{11}{12}$