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.Driti and Raji attempted all
questions (i) Driti scored 20 marks. If she has got 10 correct answers, how many questions has
she attempted incorrectly? (ii) If Raji got 12 correct answers and remaining wrong ,find her score.

Answer 1

Answer:

positive marks given for correct answer = 3

negative marks given for incorrect answer = 2

Driti scored = 20 marks

10 correct answer = 10 × 3 = 30

30 - 20 = 10

10/2 = 5

5 incorrect answer

Answer 2

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.Driti and Raji attempted all questions

(i) Driti scored 20 marks. If she has got 10 correct answers, how many questions has she attempted incorrectly?

(ii) If Raji got 12 correct answers and remaining wrong ,find her score.

Solutions :

i) Total marks scored by Driti → 20

She has 10 correct answers

Marks for each correct answer = 3

So marks for 10 correct answers = 10 × 3 = 30 marks

But in total she scored 20 but the actual marks is 30

So marks deducted = 30 – 20 = 10

Marks for every wrong answer = 2

$\sf So \: no \: of \: wrong \: answers = \frac{10}{2} = 5$

Therefore Driti attempted 5 questions incorrectly

______________________________________________________

ii) As we know that Driti attempted 15 questions

So Raji must attempt 15 questions too

So if 12 answers got correct

Then no of wrong answers = 15 – 12 = 3

Therefore she gave 3 incorrect answers

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

Marks deducted for each correct answer = 2

Marks deducted for 3 correct answers = 3 × 2 = 6

So marks scored by Raji → Correct answers – Incorrect answers

→ 36 – 6

→ 30

So she scored 30 marks in total