Ramesh ranked 16th from the top and 21 from the bottom in his class in an examination. If only 21 students passed the exam, how many students in his class failed?

Let's find the total number of students in Ramesh's class using the information given: Total students in the class = Ramesh's rank from the top + Ramesh's rank from the bottom - 1 (since Ramesh is counted twice) Total students = 16 + 21 - 1 = 36 Now, we know that only 21 students passed the exam. Therefore, the number of students who failed is: Total students in the class - Students who passed the exam = Students who failed 36 - 21 = 15 So, the correct answer is option 3. 15.