Question

Ch triplebond C-Ch=C-Ch2-OCh3

Answer 1

C-CH-CTRIPLEBONDCH-OH-CH3

Answer 2

When double bond and triple bond are at equivalent postions(double bond from left is first and triple bond is first fron right side) then, preference is given to double bond while numbering. As in your question.

But-1-ene-3-yne.

However if the double bond and triple bond are not at equivalent positions, then, whichever gets lower numbering is preferred. For example.

[math]C{H_3} - CH = CH - C \equiv CH[/math]