math
posted by matt .
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?

math 
rbowh
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 
math 
matt
How do you that rbowh? I am really bad at this.(step by step please)

math 
Ms. Sue
What part of the explanation don't you understand?

math 
matt
How to solve for x.(i am terrible at this)

math 
rbowh
what did you get when you added the two equations?

math 
matt
That is what I don't get.Please can you show me how to do it.

math 
rbowh
by the way, x represents number of correct answers  I left that out initially

math 
matt
Step by step is what I meant.

math 
rbowh
(3x  y) + (x + y) = 18 + 10
4 x = 28
x = ? 
math 
matt
Thank you very kind sir/ma'am you were a big help.

math 
rbowh
You're welcome Matt.

math 
ANIKA
3*0=0
3*1=3
3*2=6
3*3=9
3*4=12
3*5=15
3*6=18 
math 
sergio
3x+y=18
x+y=10
x=4
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