Question 1140577
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The ODDS IN FAVOR OF an event, usually expressed as a ratio A:B, compares the number of favorable outcomes (A) to the number of unfavorable outcomes (B).<br>
The PROBABILITY of an event, usually expressed as a fraction, compares the number of good outcomes to the total number of outcomes.  For the odds A:B, the total number of outcomes is A+B; so the corresponding probability is A/(A+B).<br>
For your example....<br>
Odds AGAINST living to 80 = 11:7<br>
-->  Odds IN FAVOR of living to 80 = 7:11<br>
--> Probability OF living to 80 = 7/(7+11) = 7/18<br>