Q132 of 147 Page 8

In a test, +3 marks are given for every correct answer and –1 mark are given for every incorrect answer. Sona attempted all the questions and scored +20 marks though she got 10 correct answers.

(i) How many incorrect answers has she attempted?


(ii) How many questions were given in the test?

Given that, score of Sona = 20

Correct answers by Sona = 10


Sona attempted all question.


The score on 1 correct answer = 3


The score on 1 incorrect answer = -1


(i). Let number of incorrect answers attempted = x


So, we can say that


Sona’s total score = 3 × (Correct answer) + (-1) × (Incorrect answer)


⇒ 20 = 3 × 10 + (-1) × y


⇒ 20 = 30 – y


⇒ y = 30 – 20


⇒ y = 10


Thus, incorrect answers she attempted were 10.


(ii). Sona attempted each and every question in the test.


Correct answers = 10


Incorrect answers = 10


Total questions in the test = Total questions attempted by Sona


⇒ Total questions in the test = Correct answers + Incorrect answers


⇒ Total questions in the test = 10 + 10


⇒ Total questions in the test = 20


Thus, questions in the test = 20


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