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.

(i) How many incorrect answers has she attempted?

(ii) How many questions were given in the test?

Answer 1

(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.

∴  Total incorrect answers  = -10/-1 = 10

(ii) Total correct answers = 10

Total incorrect answers = 10 (From (i) part)

∴ Total questions given in the test = 10 + 10 = 20