Question 482871: The campus vets club is having a raffle and is selling 1,100 tickets. If the people on your floor of the dorm bought 187 of those tickets, what is the probability that someone on your floor will hold the winning ticket? (Enter your answer as a decimal.)
This is the very first time that I have ever see this sort of math.Can I get a tutor to help me solve this problem? Thanks
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! This is a problem very similar to those that involve rolling a die or drawing a specific card from a deck of cards. The method to use is look at the total number of possible outcomes and divide that number into the number of possible selections that would win.
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For example, a die has 6 possible outcomes. When you roll it you can get 1, 2, 3, 4, 5, or 6. What is the possibility that you will roll an even number? There are three winning numbers ... 2, 4, or 6 are the even numbers. Therefore, when you roll a die you have three possibilities to "win" out of six possible outcomes. The probability that you will win is 3 divided by 6 which is 1/2 or in decimal form is 0.50 (50 percent).
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Similarly, the odds of rolling an odd number (1, 3, or 5) are 3 chances out of 6 possible outcomes. So the odds of rolling an odd number are 3 divided by 6 or 0.50 also.
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Note that the odds of rolling either an even number or an odd number are 6 out of 6 or 1.00 meaning you have a 100% chance of winning. This is the same as the probability of rolling an even number (0.50) plus the probability of rolling an odd number (0.50) and that sum is 1.00.
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With cards. Given a fair deck (unmarked backs) of 52 cards, what is the probability of drawing a spade on a single draw? There are 13 spades in the deck, so on any single draw your chances of drawing a spade are 13 out of 52 possible cards. So the probability of drawing a spade is 13 divided by 52 which reduces to 1/4 and the decimal equivalent is 0.25. You have a 25% chance of drawing a spade on a single draw.
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Or how about on a single draw from the deck of 52, what are the odds that you will draw an ace? There are four aces in the deck, so the number of "winners" is 4 out of the 52 possible outcomes. Divide 4 by 52 which reduces to 1 divided by 13 and in decimal form the answer is a probability of 0.076923076
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Now to your specific problem. 1100 tickets are sold. Your people on your dorm room floor own 187 of them. So when the drawing occurs you have 187 possible winners of the 1100 tickets. The probability of a winning number being held by somebody on your floor is 187 divided by 1100. If you do that division you get an answer of 0.17 as the probability of winning. (This means you have a 17% chance of having the winner be from your floor.)
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Hope this brief description gives you a little more insight into the workings of probability.
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