Question

Sohan have to do 60 questions.2 marks are given for each correct answer and 1/3 mark is deducted for every wrong answer. He got 50 marks. How many questions he did wrong?

Answer 1

Answer:

18

Step-by-step explanation:

Let Sohan get x questions right,

Then, no. of wrong questions = 60-x

Marks for each right question = 2

Marks for each wrong question = (-1/3)

According to the question,

2*x+(-1/3)*(60-x)=50

=> 2x+[(-1/3)60-(-1/3)x]=50

=> 2x-20+(x/3)=50

=> (6x/3)-20+(x/3)=50 (Taken LCM)

=> (5x/3)-20=50

=> (5x/3)=50+20

=> (5x/3)=70

=> 5x=70*3

=> 5x=210

=> x=(210/5)

=> x=42

No. of correct answers = 42

Hence, No. of incorrect answers = 60-42

= 18

Done!

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