Out of 180 questions, he must have skipped a question and an incorrect question. For an incorrect question 5 marks deducted and for skipping a question 4 marks deducted. So 720-(5+4) = 711

Maximum marks= 720 (4 marks per correct question, 180 total questions)

1. Physics= 45 questions (180 marks)

2. Chemistry- 45 questions (180 marks)

3. Biology= 90 questions (360 marks)

For every correct question, you get 4 marks, and for every wrong answer, 1 mark is deducted. (or 5 marks deducted from your total marks, including wrong).

As the candidate scored 711 marks, he/she must have attempted 179 questions, out of which 1 was wrong (179x4= 716, and for 1 wrong quesrion -5 from the Total, ie 716-5= 711)