SOLUTION: on a test 20 problems are given. Five points for each correct answer, 2 points deducted for each incorrect answer. how many correct answered are required to score 79 on the test
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Question 1008728: on a test 20 problems are given. Five points for each correct answer, 2 points deducted for each incorrect answer. how many correct answered are required to score 79 on the test Answer by fractalier(6550) (Show Source):
You can put this solution on YOUR website! Call correct answers x and wrong answers y. Then we have
x + y = 20 and
5x - 2y = 79
Now multiply the top equation by 5 and subtract it from the second equation and get
5x - 2y = 79
-(5x + 5y = 100)
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-7y = -21
y = 3 wrong answers leaving
x = 17 right answers
