Question

Veena took an objective type examination in

which there are 50 questions. If student answer

correctly, 4 Marks will be given and if answer

incorrectly 1 mark will be deducted. If Veena

answered all the questions and had achieved 80

marks. Find the number of questions which has

correct answers and incorrect answers given by

Veena?



please give right answer

​

Answer 1

Answer:

20 answers are correct

30 answers incorrect

because 4 divided by 80

20

Answer 2

The number of questions, which has correct answers is 26 and incorrect answers is 24.

Given,

Total questions in an exam Veena took = 50,

Answered correctly gives 4 marks,

Answered incorrectly results in 4 marks deduction,

Veena answered all questions and scored = 80 marks.

To find,

The number of questions which has answers correct and incorrect.

Solution,

Firstly, let the number of questions Veena answered correctly be x, and the number of her incorrect answers be y.

Now, since Veena answered all the questions, and total questions are 50. So,

$x + y = 50 \hfill ...(1)$

Her score is 80, and according to question,

correct answer = +4 marks,

incorrect answer = -1 mark.

So, for Veena, we can write,

$4x-y=80 \hfill ...(2)$

Solving the equations (1) and (2) will give us x and y, that is, the correct and incorrect answers given by Veena.

Adding both the equations, (1) + (2), we get,

$x+y+4x-y= 50 +80$

$\implies x+4x+y-y=130$

$\implies 5x=130\\\implies x = \frac{130}{5} = 26.$

⇒ x = 26.

⇒ correct answers = 26.

Now, from (1), we have,

y = 50 - x

⇒ y = 50 - 26

⇒ y = 24.

⇒ incorrect answers = 24.

Therefore, the number of questions which has correct answers is 26 and incorrect answers is 24.

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