Example 4 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) Gurpreet attempts all questions but only 9 of her answers are correct. What is her total score?
Total questions = 15
Marks for correct answer = +4
Marks for incorrect answer = −2
Number of correct answer = 9
Marks for correct answer = 4 × 9
= 36
Number of incorrect answers = Total questions − No. of correct answer
= 15 − 9 = 6
Marks for incorrect answer = 6 × (−2)
= −12
Therefore,
Total marks = 36 + (−12)
= 36 − 12
= 24
Example 4 In a class test containing 15 questions, 4 marks are given for every correct answer and (–2) marks are given for every incorrect answer (ii) One of her friends gets only 5 answers correct. What will be her score?
Number of correct answers = 5
Marks for correct answers = 5 × 4
= 20
Number incorrect answers = Total questions − No. of correct answer
= 15 − 5
= 10
Marks for incorrect answers = 10 × (−2) = −20
Total marks = 20 + (−20)
= 20 − 20
= 0

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.