Answer :
Mean = Sum of points / Number of points ;
27 = ( 25 + 28 + 36 + 21 + 28 + 15 + 24 + 30 + x ) / 9 ;
243 = 207 + x ;
x = 36 is the number ;
27 = ( 25 + 28 + 36 + 21 + 28 + 15 + 24 + 30 + x ) / 9 ;
243 = 207 + x ;
x = 36 is the number ;