2(x+y)÷2=46÷2，

x+y=23，

x+y-x=23-x，

y = 23-x；

Bring y=23-x into x+x+x+y=54,

x+x+x+23-x=54，

2x+23=54，

2x+23-23=54-23，

2x \2 = 3 1 \2，

x = 15.5；

y = 23- 15.5 = 7.5；

A: X and Y are 15.5 and 7.5 respectively.

Analysis: from x+x+y+y=46 to 2(x+y)=46, then divide both sides of the property equation by 2 at the same time according to the equation, and then subtract x at the same time to get y = 23-x; Then y=23-x brings x+x+x+y=54, which becomes x+x+x+23-x=54. Simplify it to 2x+23=54, then subtract 23 from both sides of the property equation according to the equation, and then divide it by 2 at the same time to get the value of x.