Algebra II : Calculating Probability
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Example Question #41 : Probability
Hector has a shelf of books. He wants to choose a random book to read. If there are 24 books on the shelf and he has an equal chance of choosing any particular one, what is the probability that he picks the third book from the left?
If Hector has a shelf of books. He wants to choose a random book to read. If there are 24 books on the shelf and he has an equal chance of choosing any particular one, what is the probability that he picks the third book from the left?
This is a wordy problem, but if we cut through to what it's asking it is fairly simple.
We need to find the probability of an event.
The event is randomly choosing a book from a book shelf.
There are 24 books total, and we need to pick 1.
So, our probability will be
So our answer is:
Example Question #42 : Probability
Julie tosses a fair coin twice, and then rolls a six-sided die. What is the probability that she will flip two tails, and roll a number other than four?
Each event is independent of another.
A fair coin has either heads or tails, which means the probability of her rolling heads or tails will be 
The probability of her rolling two tails is:
In a six sided dice, the odds of rolling any particular number is one-sixth.
If Julie was to roll a number other than four, this means that she has five out of six possible rolls that she can land on.
The probability of rolling a number other than four is:
Multiply the probabilities.
The answer is:
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