pls answer fassttttt

Dear student,

mean marks of 40 students of one section = 60
the sum marks of 40 students of that section = 60×40 = 2400

Mean marks of 60 students of second section=80
The sum marks of 60 students of second section=80×60=4800

Total marks of (60+40)100 students=(2400+4800)=7200
Mean marks of 100 students=7200/100=72

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