if the width were doubled,new width=2y
length were increased by 23 m, new length=(x+23)
new perimeter=2(2y+x+23)=(4y+2x+46)=232 metres
4y+2x+46=232
4y+2x=232-46
2x+4y=186
x+2y=93....[2]
Taking equations 1 and 2 together we get,
x+y=56
x+2y=93
subtract equation[1] from [2]
x+2y-(x+y)=93-56
x+2y-x-y=93-56
2y-y=37
y=37
x+y=56
x=56-y=56-37=19
x=19 metres,y=37 metres
Hope this helps,
Prabhat