We shall find the overall percentage (for all the seven students) with respect to each subject. The overall percentage for any subject is equal to the average of percentages obtained by all the seven students since the maximum marks for any subject is the same for all the students. Therefore, overall percentage for: (i) Maths = 1 x (90 + 100 + 90 + 80 + 80 + 70 + 65) % 7 = 1 x (575) % 7 = 82.14%. (ii) Chemistry = 1 x (50 + 80 + 60 + 65 + 65 + 75 + 35) % 7 = 1 x (430) % 7 = 61.43%. (iii) Physics = 1 x (90 + 80 + 70 + 80 + 85 + 65 + 50) % 7 = 1 x (520) % 7 = 74.29%. (iv) Geography = 1 x (60 + 40 + 70 + 80 + 95 + 85 + 77) % 7 = 1 x (507) % 7 = 72.43%. (v) History = 1 x (70 + 80 + 90 + 60 + 50 + 40 + 80) % 7 = 1 x (470) % 7 = 67.14%. (vi) Comp. Science = 1 x (80 + 70 + 70 + 60 + 90 + 60 + 80) % 7 = 1 x (510) % 7 = 72.86%. Clearly, this percentage is highest for Maths.