[ARCHIVED THREAD] - Todays math problem (Page 1 of 2)
Posted: 9/27/2012 8:10:31 AM EDT
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There is no correct answer. If the answer was 25%, you would have a 50% chance of picking it at random. Does not compute. If the answer was 50% or 60%, you would have a 25% chance of picking it at random. Does not compute. Or looking at it another way, all answers are correct, because the question stipulates you are to choose an answer at random, instead of basing it on validity. |
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B = means you read the values and based your response on what a "random" selection could result in, seeing as two of the options are the same value
A or D = means you are responding to the question based on the fact that there are 4 options and you can only choose one - but this in itself is illogical because you can only pick one Not = means you either don't understand the question, or you don't agree with the problem, or you don't think that the correct answer is an option I choose potato. 
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The probability is .375. Although there are only three possible numbers to choose, there are four choices. Eliminate D as an option since it is the same as A. If the tester chooses 25%, it does not matter if he chose A or D. So it does matter which one the student chooses.
The choices are A,B,C,A. Next, count each choice with each possible correct answer. The first letter is the 'correct' letter. The second letter is the one the student chose. These are all the possible outcomes: AA,AB,AC,AA BA,BB,BC,BA CA,CB,CC,CA AA,AB,AC,AA There are 6 outcomes where the the first and second letters are the same: AA,AA,BB,CC,AA,AA. There are 16 choices. Therefore there will be a match of 'correct' number and choice in 6 of 16 trials. 6/16 = 3/8 = .375. |
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Quoted: The probability is .375. Although there are only three possible numbers to choose, there are four choices. Eliminate D as an option since it is the same as A. If the tester chooses 25%, it does not matter if he chose A or D. So it does matter which one the student chooses. The choices are A,B,C,A. Next, count each choice with each possible correct answer. The first letter is the 'correct' letter. The second letter is the one the student chose. These are all the possible outcomes: AA,AB,AC,AA BA,BB,BC,BA CA,CB,CC,CA AA,AB,AC,AA There are 6 outcomes where the the first and second letters are the same: AA,AA,BB,CC,AA,AA. There are 16 choices. Therefore there will be a match of 'correct' number and choice in 6 of 16 trials. 6/16 = 3/8 = .375. I am the teacher and I say A and D are separate and distinct choices despite having the same value. My answer key has D as the correct answer, not A. |
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The first assumption is that there IS a correct answer to be chosen. If you asked the problem this way:
There are 4 marbles in a bag. 2 red (25%), 1 blue (50%), one green and one green (60%). What are the odds of picking a red one on the first try? Your odds are 50% because red represents half of the available choices. But in the original problem, you're not asked to pick red, you're asked to pick "the right marble", which has no answer. So in the original problem: If the correct answer was A, your odds are 50% because "25%" being listed twice, represents half of the available choices. If the correct answer was B, your odds are 25%. it does not matter that 25% is listed twice. If 25% was listed three times, you'd still have a 1:4 chance of picking 50% If the correct answer was C, your odds are 25%. it does not matter that 25% is listed twice. If 25% was listed three times, you'd still have a 1:4 chance of picking 60% So, there is no answer because there is no answer. |
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by randomly picking an answer out of 4 questions you have 25% chance of getting it right. 2 out of 4 answers are 25% so this would make it 50% chance of getting the right answer.
Since 50% is the right answer to the question, you now only have a 25% chance of getting it right. Which brings me to my next Suck It. |
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Quoted:
Quoted:
The probability is .375. Although there are only three possible numbers to choose, there are four choices. Eliminate D as an option since it is the same as A. If the tester chooses 25%, it does not matter if he chose A or D. So it does matter which one the student chooses. The choices are A,B,C,A. Next, count each choice with each possible correct answer. The first letter is the 'correct' letter. The second letter is the one the student chose. These are all the possible outcomes: AA,AB,AC,AA BA,BB,BC,BA CA,CB,CC,CA AA,AB,AC,AA There are 6 outcomes where the the first and second letters are the same: AA,AA,BB,CC,AA,AA. There are 16 choices. Therefore there will be a match of 'correct' number and choice in 6 of 16 trials. 6/16 = 3/8 = .375. I am the teacher and I say A and D are separate and distinct choices despite having the same value. My answer key has D as the correct answer, not A. 
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