A blood plasma donation company accepts 404040 volunteers per day. Based on previous data, they know that 15\%15%15, percent of
2 answers:
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Answer:
<em>The viewer mistakenly determined that one of the equations in the system should be 2 x + y = 28. Instead modifications should have been made before applying the equation.</em>
Step-by-step explanation:
Given
Total Questions = 20
Total Points = 28
Correct Answers = +2 points
Incorrect Answers = -1 point
Required
Spot the error in the viewer's calculation
The viewer represents the correct answers with x and the incorrect ones with y.
This implies that
Also, for every correct answers, she gets 2 points;
<em>This can be represented by 2x</em>
and for every incorrect answers, she gets -1 point
<em>This can be represented by -y</em>
This implies that
This is where the viewer made a mistake
The viewer's mistake is that; instead of subtracting total incorrect points from the correct points, the viewer added them together;
Solving further
Add both equations together
Divide both sides by 3
Substitute in
Subtract 16 from both sides
<em>This implies that the contestant answered 16 questions correctly and 4 questions incorrectly</em>
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