SOLUTION: David entered a quiz. For each correct answer three points were added; for each incorrect answer one point was deducted.The quiz had 100 questions and David scored 176 points. How

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Question 875702: David entered a quiz. For each correct answer three points were added; for each incorrect answer one point was deducted.The quiz had 100 questions and David scored 176 points. How many questions did he answer correctly?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
correct answers be x
and wrong answers be y
x+y=100
3x-y=176
x= number of correct answers
y= number of wrong answers

1 x + 1 y = 100 .............1

3 x -1 y = 176 .............2
Eliminate y
multiply (1)by 1
Multiply (2) by 1
1 x 1 y = 100
3 x -1 y = 176
Add the two equations
4 x = 276
/ 4
x = 69
plug value of x in (1)
1 x + 1 y = 100
69 + y = 100
y = 100 -69
y = 31
y = 31
x= 69 number of correct answers
y= 31 number of wrong answers
m.ananth@hotmail.ca