SOLUTION: at a mathematics Quiz 30 problems were given. each correct answer earned 4 points and 2 points were deducted for each incorrect answer andrew answered all but one of the problems,

Question 981523: at a mathematics Quiz 30 problems were given. each correct answer earned 4 points and 2 points were deducted for each incorrect answer andrew answered all but one of the problems, scoring 86 points how many correct answer did he have
Answer by macston(5194) (Show Source): You can put this solution on YOUR website!
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C=correct answers; I=incorrect answers; A=total answered=29
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I+C=A
I+C=29
I=29-C Use to substitute for I below.
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4C-2I=86 Substitute for I from above.
4C-(2)(29-C)=86
4C-58+2C=86 Add 58 to each side.
6C=144 Divide each side by 6.
C=24 ANSWER: Andrew answered 24 questions correctly.
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CHECK:
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I-29-C=29-24=5
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4C-2I=86
4(24)-2(5)=86
96-10=86
86=86
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