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Question
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.
- How many incorrect answers has she attempted?
- How many questions were given in the test?
Solution
i. Total marks scored by Sona = 20
Total correct answers = 10
∴ Marks for correct answers = 10 × 3 = 30
but she got 20 marks.
∴ Marks for incorrect answers = 20 – 30 = – 10
–1 mark is given for every incorrect answer.
ii. Total correct answers = 10
Total incorrect answers = 10 ...(From (i) part)
∴ Total questions given in the test = 10 + 10 = 20
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