Question

A test has 80 questions. There is one mark for a correct answer, while there is a negative penalty of -1/2 for a wrong answer and -1/4 for an unattempted question. What is the number of questions answered correctly, it is known that he has left 10 questions answered and scored 34.5 marks. Find the number of correct answer. A) 45 B) 48 C) 54 D) 50​

Answer 1

Step-by-step explanation:

Total Questions = 80

questions attempt नहीं किए = 10

10 question attempt नहीं करने पर -2.5 अंक

काट दिए गए।

फिर शेष questions = 70

सही questions किए = 48

questions गलत किए = 22

अत: 48*1+22*(-1/2)+10*(-1/4)

48-11-2.5

37-2.5 = 34.5 अंक

अत: सही हुए questions = 48

Answer 2

Answer:

Number of correct answers are 48.

Step-by-step explanation:

Let number of correct answers = x

And number of Incorrect answers = y

Total questions = 80

Unattempted questions = 10

Attempted questions = 80 - 10 = 70questions

Number of correct answers + Number of incorrect answers = Attempted questions

x + y = 70  ... Equation 1

Now,

Total Marks = 80

Marks deducted for 10 unattempted questions = $10\times \frac{1}{4}$= 2.5 marks

Marks scored = 34.5

Now according to question,

Marks for correct answers - Marks for incorrect answers - Marks for unattempted questions = Marks Scored

$1x - \frac{1}{2}\times y - 2.5 = 34.5$

$x - \frac{y}{2} =37$   .... Equation 2

Now, solving equation 1 and 2 we get

$( 70 - y ) - \frac{y}{2} = 37$

$y=22$

Incorrect answers = y = 22

Correct answers = x = 48

Hence, he scored 48 correct answers.