Question

In a class test (+5) marks are given for every correct answer and (-2) for every incorrect answer. No marks are given for not attempting any question

(I) Radhika scored 20 marks. If she has got 12 correct questions. How many questions has she attempted incorrectly.

(II) Mohini scores -5 marks in this test though she has got 7 correct. How many questions has she attempted incorrectly

Answer 1

1.
Let x be the number of incorrect answers she got. She got 12 correct answers.

5∗12 + (−2)∗x=20
-2x = -40
x= 20


Hence number of incorrect answers is 20.


2.

Let x be the number of incorrect answers she got. She got 7 correct answers.
5∗7 + (−2)∗x=-5
-2x = -40
x= 20

total quest = correct + incorrect

= 20 + 7 = 27