Q. 1324.3( 10 Votes )
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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