In a class containing 10 questions, ‘3’ marks are awarded for every correct answer and (-1) mark is for every incorrect answer and ‘0’ for questions not attempted.
(i) Gopi gets 5 correct and 5 incorrect. What is his score?
(ii) Reshma gets 7 correct answers and 3 incorrect answers. What is the score?
(iii) Hena gets 3 correct and 4 incorrect answers out of seven questions she attempts. What is the score?

Hint: In this question it is given that, in a class containing 10 questions, ‘3’ marks are awarded for every correct answer and (-1) mark is for every incorrect answer and ‘0’ for questions not attempted. So we have to find the scores of Gopi, Reshma and Hena. So for this we have to multiply ‘3’ for every correct answer and (-1) for every incorrect answer. So let us say for any student who gave ‘x’ right questions and ‘y’ wrong questions then total marks is given as 3x+(−1)y i.e, 3x−y total marks.

Complete step-by-step answer:
(i) Gopi gets 5 correct answers, i.e, x = 5.
So the marks for correct answers is $3\times 5$= 15
And 5 incorrect answers,i.e, y = 5.
So the marks deducted $1\times 5$)= 5
Therefore, the score = 3x-y =15-5 =10 marks.
(ii) Reshma gets 7 correct answers and 3 incorrect answers, i,e, x = 7 and y = 3,
Similarly, we can write, the score = $3\times 7-1\times 3$ =21-3 = 18 mark
(iii) Hena gets 3 correct and 4 incorrect answers out of seven questions she attempts.
So we can write, x = 3 and y = 4,
Therefore, Hena’s score = $3\times 3-1\times 4$ = 9-4 =5 marks.

Note: Here it is given that one gets (-1) for every incorrect answer, so if you write (-1) then you have to write like this: the marks(-1) gets added for every incorrect answer, and if you write (+1) then you need to write: the marks (+1) gets subtracted for every incorrect answer.