Answer:
a. 4 marks b. 9 questions
Explanation:
a) Anu gets 8 correct answer and 12 incorrect answers what is her score?
Since Anu got 8 correct answer and 12 incorrect answers, and + 5 marks is given for every correct answer and (-3) marks are given for every incorrect answer, the total score for correct answers is number of correct answer × marks for correct answer = 8 × (+ 5) = 40.
Also, the total score for incorrect answers is number of incorrect answer × marks for incorrect answer = 12 × (- 3) = -36.
Anu's total score = total score for correct answers + total score for incorrect answers = 40 + (-36) = 40 - 36 = 4 marks.
So, Anu scored 4 marks.
b) Sam answered all the questions and scored 28 marks though he got 11 correct answers. How many incorrect answers had he attempted?
Let x be the number of incorrect answers. Since the marks for incorrect answers is -3, then his total score for incorrect answers is -3x.
Since Sam got 11 correct answers and is given + 5 marks for each correct answer, then his total score for correct answers is 11 × (+5) = +55.
Since he gets a total of 28 marks, we have that total score for incorrect answer + total score for correct answer = 28.
So, -3x + 55 = 28
Solving for x, we have
-3x = 28 - 55
-3x = -27
x = -27/-3
x = 9
Since x = 9, Sam attempted 9 incorrect questions.
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