A competitive exam is to be held on a particular day. The examiner who has to supervise the exam, enters the examination room 30 minutes before 2:30 hours. He came 40 minutes before the student who was 20 minutes late for the exam. At what time will the examination start?

Given:
· The examiner entered the examination room 30 minutes before the exam start time.
· The student arrived 40 minutes after the examiner.
· This same student was 20 minutes late for the exam, meaning the student arrived 20 minutes after the exam start time.
Time of examiner enters the examination room = 2: 00 hours
examiner came 40 minutes before the student who was 20 minutes late for the exam means the time of student who was 20 minutes late = 2 : 40 hours
Student was late = 20 minutes
Thus, the time of the examination start will be 2 : 40 – 20 minutes = 2 : 20 hours.
Thus, the correct answer is (b) 2:20 hours​​