Question

Question 132

In a test, +3 marks are given for every correct answer and - 1 mark is 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?

Answer 1

Let x be the correct answers and y be the incorrect answers, given by Sona.
It is given that, if she gives 10 correct answers and her score is 20, Since, for every correct answer, +3 is given and for every incorrect answer, -1 is given.
(i) 3 $\times$ (Correct answer) + (-1) $\times$ (Incorrect answer) = Total score
$\Rightarrow 3\times 10+(-1)\times y=20\Rightarrow 30-y=20\Rightarrow 30-20=y\Rightarrow y=10$
(ii) Total number of questions = Correct answer + Incorrect answer
= x + y = 10 + 10 = 20