Aggregate marks obtained by Tarun

    = [ (65% of 150) + (35% of 130) + (50% of 120)

          + ((77% of 100) + (80% of 60) + (80% of 40) ]

    = [ 97.5 + 45.5 + 60 + 77 + 48 + 32 ]

    = 360.

The maximum marks (of all the six subjects)

    = (150 + 130 + 120 + 100 + 60 + 40)

    = 600.

Overall percentage of Tarun =		360	x 100		% = 60%.
		600

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.

Aggregate marks obtained by Sajal

    = [ (90% of 150) + (60% of 130) + (70% of 120)

          + (70% of 100) + (90% of 60) + (70% of 40) ]

    = [ 135 + 78 + 84 + 70 + 54 + 28 ]

    = 449.

From the table it is clear that Sajal and Rohit have 60% or more marks in each of the six subjects.

Average marks obtained in Physics by all the seven students