Saturday, June 16, 2012
Summer vacation 2012 problems ... The first two problems
Problem m01-22/ Twenty questions
On a twenty-question test, each correct answer is worth five points, each unanswered question is worth one point, and each incorrect answer is worth zero points. which of the following scores is not possible?
(a) 90 (b) 91 (c) 92 (d) 95 (e) 97
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Hints
To get a score in the nineties, a student must have more than seventeen correct answers. If a student had eighteen correct, but didn't answer the two remaining questions, the score would be 90 + 1+1= 92.
Problem m01-21/ A little statistics review
The mean (aka average or moyenne) of a set of five different positive integerd is 15. The median is 18. The maximum possible value of the largest of these five integers is
(a) 19 (b) 24 (c) 32 (d) 35 (e) 40
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Hints
We know what the sum of the five numbers is. (Think about how you calculate a mean/average/moyenne.)
We know that two of the numbers < 18 and two of the numbers > 18, and one of the numbers = 18
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