In a class test containing 15 questions, 4 marks are given for every correct answer and (–2) marks are given for every incorrect answer. (i) Bharathi attempts all questions but only 9 answers are correct. What is her total score? (ii) One of her friends Hema attempts only 5 questions and all are correct. What will be her total score?
SCERT Class 7 Telangana, Maths Chapter 1 Integers
Answers
Answer : Scores of Bharathi and hema are 24 , 20 respectively.
Given that,
In a class test containing 15 questions, 4 marks are given for every correct answer and (–2) marks are given for every incorrect answer.
Let the number of correct answer = x
Number of incorrect answers = y
Marks obtained by the student = 4(x) - 2y
Case(1) Bharathi attempts all questions.
Number of correct answers = 9
Number of incorrect = 15 - 9 = 6
So, x = 9, y = 6
Total score = 4x - 2y = 4(9) - 2 (6) = 36 - 12 = 24
Case(2) Hema attempts only 5 questions. All are correct.
So, Number of correct answers = 5
Incorrect Answers = 0
x = 5, y = 0
Total score = 4x - 2y = 4(5) - 2 (0) = 4(5)= 20 .
Therefore, Bharathi score is 24 , Hema score is 20 .
Answer:
mark rewarded for one correct answer=4
mark reduced for one wrong answer=(-2)
(i)mark for 9 correct answers=9*4=36
mark for 6 wrong answers=6*(-2)=(-12)
total mark=36-12=24
(ii)mark for 5 correct answers=5*4=20
no wrong answer=no marks reduced
total mark=20