Question

1. In a class test (+ 5) marks are given for every correct answer and (–2) marks are given for every incorrect answer and no marks for not attempting any question.
(i) Rayan scored 30 marks. If she has got 10 correct answers, how many questions has she attempted incorrectly?
(ii)Riya scores 44 marks by attempting 13 questions. How many questions has he attempted correctly and how many has he attempted incorrectly?

Answer 1

Solution :

We find a relation,

5x - 2y = M; x = correct answers

y = incorrect answers

M = marks obtained

(i)

• Rayan scored 30 marks.
• He has got 10 correct answers.
• Given, M = 30 and x = 10

From the above relation, we get

5 (10) - 2y = 30

or, 50 - 2y = 30

or, 2y = 20

or, y = 10

Answer: Rayan has attempted 10 questions incorrectly.

(ii)

• Riya scores 44 marks.
• She attempted 13 questions.

• Let correct answers = x
• Then incorrect answers = 13 - x
• M = 44

From the above relation, we get

5x - 2 (13 - x) = 44

or, 5x - 26 + 2x = 44

or, 7x = 70

or, x = 10

Then y = 3

Answer: She has given 10 correct answers and 3 incorrect answers.