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anonymous

  • one year ago

On a certain multiple-choice test, 9 points are awarded for each correct answer, and 7 points are deducted for each incorrect or unanswered question. Sally received a total score of 0 points on the test. If the test has fewer than 30 questions, how many questions are on the test?

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  1. DanJS
    • one year ago
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    9*(#correct) - 7*(#wrong) = 0 --given

  2. DanJS
    • one year ago
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    there are two variables there and only one equation, need one more to be able to solve

  3. anonymous
    • one year ago
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    Cannot be determined 16 19 21 24

  4. DanJS
    • one year ago
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    If the test has fewer than 30 questions... that is the second given thing

  5. DanJS
    • one year ago
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    Total questions = #correct + #wrong

  6. DanJS
    • one year ago
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    which is less than 30

  7. campbell_st
    • one year ago
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    just write it as a ratio 9 correct = 7wrong so the ratio is 9:7 16 parts so 7 correct and 9 wrong

  8. DanJS
    • one year ago
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    that works

  9. anonymous
    • one year ago
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    can we also use 9x7 and 7x9 ?

  10. DanJS
    • one year ago
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    what cambell did was take the first equation that was given.. 9*(#correct) - 7*(#wrong) = 0 and solve it as a ratio of correct/wrong

  11. DanJS
    • one year ago
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    and the total correct and wrong has to be less than 30

  12. anonymous
    • one year ago
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    |dw:1441233943898:dw|

  13. DanJS
    • one year ago
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    no...

  14. anonymous
    • one year ago
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    yesssssss because 63 -63= 0

  15. DanJS
    • one year ago
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    9*(#correct) - 7*(#wrong) = 0 you have to have correct = 7 and wrong = 9, otherwise it is not true

  16. DanJS
    • one year ago
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    the correct and wrong answers are worth different points

  17. anonymous
    • one year ago
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    yea thats what i did dont u see it?

  18. anonymous
    • one year ago
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    9 points for 7 questions which equals to 63 and 7 points for 9 questions which is 63 deducted so total equals 0

  19. DanJS
    • one year ago
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    sorry if i read something wrong... this is the summary of it...second

  20. DanJS
    • one year ago
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    let: #right = R and # wrong = W --------------------------------- given: 9*R - 7*W = 0 and R + W < 30 --------------------- solve for ratio of R vs W from the first equation... \[\frac{ R }{ W }=\frac{ 7 }{ 9 }\]

  21. anonymous
    • one year ago
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    yea thats what i did. Thank youuuu =)

  22. DanJS
    • one year ago
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    with having 7 right and 9 wrong, comes out to zero points...

  23. DanJS
    • one year ago
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    7+9 is 16 questions... the next choice is 32 questions, but that is too much . 14 right and 18 wrong

  24. DanJS
    • one year ago
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    k welcome

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