Question

In a class test (+3) marks are given for every correct answer and (–2) marks are given for every incorrect answer and no marks for not attempting any question. Radhika scored 20 marks. If she has got 12 correct answers, how many questions has she attempted incorrectly? 

Answer 1

Marks scored for 1 correct answer = +3

Marks scored for 1 incorrect answer = −2

Marks scored by Radhika = 20

Marks scored for 12 correct answers = 12 × 3 = 36

Marks scored for incorrect answers = Total marks scored − Marks scored for 12 correct answers

= 20 − 36

= −16

Marks scored for 1 incorrect answer = −2

Thus, number of incorrect answers = (−16) ÷ (−2)

= 8

Therefore, she attempted 8 questions incorrectly.