Quick maths question- should be no problem for you clever clogs.?

10. There are 12 boys and 15 girls in a class.





In a test the mean mark for the boys was n.





In the same test the mean mark for the girls was m.





Work out an expression for the mean mark of the whole class of 27 students.








I'm stuck :)

Quick maths question- should be no problem for you clever clogs.?
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(12n+15m)/27
Reply:Mean marks means average marks for any one of boy(or girl)


Mean(Average) marks for 12 boys=n


Total marks for all boys=12*n


Mean(Average) marks for 15 girls=m


Total marks for all girls=15*m


Total marks of all 27 boys and girls=Total marks for all boys+Total marks for all girls


Total marks of all 27 boys and girls=12n+15m


Mean marks of each one of 27 students=(12n+15m)/27
Reply:(12n + 15m)/27
Reply:(12n + 15m)/27
Reply:(12n+15m)all over27



CAT