Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A weather report says that the odds in favour of rain tomorrow are to . Find the probability of rain and the probability of no rain. On another day, the probability that a train is late is . Write the odds in favour of a late train in the form in lowest terms, and give and .
For equally likely outcomes, . In general the probabilities of the simple events are at least and add up to , and . For at least one, use . Odds of in favour mean .
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Rain. Odds mean parts for and parts against. So .
Step 2. No rain. , which is .
Step 3. The late train. means cases for out of , so against. The odds in favour are . Divide both by to get .
Answer: and , and the odds .
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