A candidate attempted 12 questions and secured full marks in all of them. If he obtained 60% in the test and all questions carried equal marks, then what is the number of questions in the test

Explanation

Let the total number of questions in the test be x. As the candidate attempted 12 questions, he left out (x – 12) questions. As he secured full marks in all 12 questions attempted, his total score from these questions is 12 (assuming each question carries 1 mark). Let the marks for each question be m. Then, the total marks in the test is x m. As the candidate obtained 60% in the test, his total score is 0.6 times the total marks in the test. Therefore, we can write: 12m + (x – 12) * 0 = 0.6 * xm Simplifying this equation, we get: 12m = 0.6xm Dividing both sides by 0.6m, we get: 20 = x Therefore, the total number of questions in the test is 20. The correct answer is option (D) 20.