mean is (54+66)/2 = 60
The Greatest Common Factor of the three numbers is 6.
36, 42, 48, 54, 60, 66 and so on.
42 48 54 60 66
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66
They are: 36, 42, 48, 54, 60, 66, 72, 78.
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, . . .
66 is greater than 54.
It is 54/66 which can be simplified, if required.
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, . . .
6 12 18 24 30 36 42 48 54 60 66 72 ............................................
36, 42, 48, 54, 60, and 66