Question

There are 90 multiple choice questions In test. Suppose u get 2 marks for every correct answer and for every question you have attempted or answer wrongly,one mark is deducted .if you get 60 marks how many questions did you answer correctly?

Answer 1

Let the correctly questions answers be x.

So, wrongly answers questions}=90-x

It is also given that we get 2 marks for every correct answer and for every question we have attempted or answer wrongly, one mark is deducted.

So, marks got for correct answers=2x

Marks got for every wrong answers= -1(90-x)

ATQ (According to the question):-

2x+(-1(90-x))=60

2x-1(90-x)=60

2x-90+x=60

2x+x=60+90

3x=150

x=150/3

x=50

So, the total answered questions is 50.

Wrongly answered questions=90-x=90-50=40

Verification:-

correct and wrong answers' marks should add up to 60

So, correct answers marks=2x=2×50=100

Wrong answers marks= -1(90-x)= -90+x= -90+50= -40

So, 100+(-40)=60

100-40=60

60=60

So, LHS=RHS, hence it is correct and verified.