Question

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

OK ITS OK IM GOD CALM DOWN

Answer 2

Explanation:

(1)

If she got 10 answers right, she got 5 * 10 = 50 marks before anything was deducted.

Since she wound up with 30 marks, she lost 50 - 30 = 20 marks. If you don't feel comfortable with this, call it -20

Each incorrect answer cost her -2 marks.

Divide -20 /-2 = 10

She has answered 10 questions incorrectly.

(ii)

5x - 2y = 44

x + y = 13 Multiply this equation by 2

2x + 2y = 26

Rewrite the first and third equations

5x - 2y = 44

2x + 2y = 26 Add

7x = 70 Divide by 7

x = 70/7

x = 10

So 10 questions were answered correctly

x + y = 13

10 + y = 13

y = 3

Answer

10 were answered correctly

3 were answered incorrectly