Question

On a multiple choice test, you can I point for each correct answer and the lose 2 points for each incorrect answer.

a. Write an expression for a student's total score.

b.Tim answered 22 questions correctly and 3 incorrectly. Find Tim's score.

Answer 1

Part A

I'm assuming you meant to say "you can get 1 point for each correct answer".

x = number of correct answers

y = number of incorrect answers

1x = points from the correct answers

2y = points you lose from the incorrect answers

1x-2y = total points

Answer: x-2y

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Part B

Tim got x = 22 questions correct and y = 3 incorrect.

So,

x-2y = 22-2*3 = 22-6 = 16

Answer: 16

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Side note: If Tim got a score of 16 out of 22+3 = 25, then the percentage is 16/25 = 0.64 = 64%. It appears that getting even a few wrong answers takes a pretty hefty toll on the final percentage.

Answer 2

Below!

Solution for Part A:

To create an expression for this, we will need to recall:

• 1 correct answer = 1 point
• 1 Incorrect answer = -2 points

Using these clues, we know that the expression is c - 2w.

Solution for Part B:

We know that:

• Total points earned = c - 2w
• c = Number of correct answers
• w = Number of incorrect answers

Work:

• 22 - 2(3) = Total points earned by Tim
• => 22 - 6 = Total points earned by Tim
• => 16 = Total points earned by Tim

Hence, Tim earned 16 points in total.