Question

In a test 1 mark is awarded for every correct answer while ¼ mark is deducted for every wrong answer. A student knew answers to some of the questions. Rest of the questions he attempted by guessing. He answered 160 questions and got 80 marks. If answer to all questions he attempted by guessing were wrong, then how many questions did he answer correctly? And How many questions did he guess?​

Answer 1

Answer:

Let the no of questions whose answer is known to the student x and questions attempted by cheating be y x + y =120 x - 1/4y = 90 solving these two x = 96 and y = 24 1. He answered 96 questions correctly. 2. He attempted 24 questions by guessing 3. Marks = 80- 1/4 of 40 =70 4. x – 1/4 of (120 - x) = 95 5x = 500, x = 100

Step-by-step explanation:

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Answer 2

Answer:

Let the no of questions whose answer is known to the student x and questions attempted by cheating be y x + y =120 x - 1/4y = 90 solving these two x = 96 and y = 24 1. He answered 96 questions correctly. 2. He attempted 24 questions by guessing 3. Marks = 80- 1/4 of 40 =70 4. x – 1/4 of (120 - x) = 95 5x = 500, x = 100