Question

In an examination , a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer . If he attempts all 200 questions and secures 240 marks , the number of questions he attempts incorrectly , is

Answer 1

Answer:112

Step-by-step explanation:

Let, he answered x questions correctly and y questions incorrectly

Then, A/C

x+y=200..........(1)

Now, since 4 marks is given for correct answer and 1 marks is lost for wrong answer

So, A/C

4x-y=240.......(2)

Multiplying (1) by 4 we get

4x+4y=800.......(3)

(3) - (2)

4y-(-y)=800-240

5y=560

y= 112

Hence, number of question he attemted incorrectly=y=112