Answer:
8:12:3
Step-by-step explanation:
Flats:Terraced is 2:3
Detached:Terraced is 1:4
First make the Terraced the same.
Flats:Terraced is 8:12
Detached:Terraced is 3:12
Terraced:Detached is 12:3
Now that we know, we can combine it.
Flats:Terraced:Detached is 8:12:3
Hope this helps :D