(Japanese) What does this mean in english: 俺とあいつが一緒の部屋ってどんなだと思う?

Question:

My trans: How is it that me and this guy share a room together?

No google or yahoo translations please.

Answer:

"How is it that me and this guy share a room together?" could be translated:
なんで（どうして） こいつと俺が一緒の部屋に暮らしてるわけ？（About current REAL life）

For your better understanding, the sentence should go like:
もし、俺とあいつが 一緒の部屋で暮らすとしたら、どんなこと（or どんな風 ふう）になると思う？, which is "the 2nd conditional sentence" that describes possible outcome of an event that is less likely to occur. So, I'd translate:

"Can you imagine what life would be like if that guy and I shared a room?"

In colloquial, ”～って（とは／としたら）どんな（ふう）だと思う” is widely used.
E.g. 愛のない世界ってどんなだと思う？（≒ 愛がないとしたら、この世はつまらないだろう）
Can you imagine the world without love? (≒ Without love, the world would be worthless)

※どんなだと思う？＝ どんなことになると思う？≒ どんなことになるか分からないでしょう
Can you imagine what life/the world will/would be like?
http://eow.alc.co.jp/%e3%81%a9%e3%82%93%…
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Or, simply: (about his CURRENT unwanted awful life)
"That guy and I share a room!! Can you imagine? (Can you believe that?)"
In this case, って（とは）どんなだと思う？describes；
"can you imagine how pleasant/terrible/miserable it is to...?", but as あいつ(kind of insulting) explains the speaker is annoyed, it should mean something NEGATIVE.