Posted by **matt** on Tuesday, April 9, 2013 at 3:03pm.

A math contest consists of ten problems.Three points are given for each correct answer. One point is deducted for each incorrect answer. Andy answers all the problems and scores 18 points. How many correct answers does he have?

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**rbowh**, Tuesday, April 9, 2013 at 3:17pm
x = number of answers

y = number of incorrect answers

3 x - y = 18

x + y = 10

add the two equations and solve for x

check your answer

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**matt**, Tuesday, April 9, 2013 at 3:20pm
How do you that rbowh? I am really bad at this.(step by step please)

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**Ms. Sue**, Tuesday, April 9, 2013 at 3:28pm
What part of the explanation don't you understand?

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**matt**, Tuesday, April 9, 2013 at 3:33pm
How to solve for x.(i am terrible at this)

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**rbowh**, Tuesday, April 9, 2013 at 3:34pm
what did you get when you added the two equations?

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**matt**, Tuesday, April 9, 2013 at 3:35pm
That is what I don't get.Please can you show me how to do it.

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**rbowh**, Tuesday, April 9, 2013 at 3:36pm
by the way, x represents number of correct answers - I left that out initially

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**matt**, Tuesday, April 9, 2013 at 3:38pm
Step by step is what I meant.

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**rbowh**, Tuesday, April 9, 2013 at 3:42pm
(3x - y) + (x + y) = 18 + 10

4 x = 28

x = ?

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**matt**, Tuesday, April 9, 2013 at 3:43pm
Thank you very kind sir/ma'am you were a big help.

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**rbowh**, Tuesday, April 9, 2013 at 3:46pm
You're welcome Matt.

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