class A9 marks (Jack's)
student  math       gym         history 
1        80         90          80
2        75         90          100
3        50         70          80
4        60         86          96
5        78         66          76
6        90         90          100
7        95         85          85
8        67         71          81
9        70         70          80
10       76         76          76
11       83         87          89
