Let  S be the sample space . Them ,

n(S) = number of ways of drawing  3 marbles out of 12.

       = `12_(C_3) = ((12 xx 11 xx 10))/((3 xx 2 xx 1))`= 220.

Let  E be the event of drawing  3 balls of the same  colour.

Then , E = event of drawing ( 3 balls out of 5) or ( balls out of 4) or ( 3 balls out of  3).

`rArr `   n(E) = `(5_(C_3) + 4_(C_3) + 3_(C_3))`

                     = `(5_(C_2) + 4_(C_1) + 1)`

                    = `((5 xx 4))/((2 xx 1)) + 4 + 1` = 15.

`rArr     P(E) = (n(E))/(n(S)) = 15/220 = 3/44`.

`:.`     Required probability  = `(1 - 3/44) = 41/44`