Q:

Sentence with いいわけない

いいかと聞かれたら、いいわけないと答えるな

The second part of the sentence is bother me. If いいわけない must mean "no excuse", then the rough translation will be: "When you asking "It's ok?" don't answer "no excuse". So, how the second part is translating?

A:

Hmm?? Isn't it 

「[良]{い}いか？」と聞かれたら、「[良]{い}い[訳]{わけ}（が）ない。」と（私なら）答えるな。/答えるなあ。

If I was asked "Is it okay?", I would answer "No way!"
(I mean, I think the な is not 禁止(negative command) but 軽い断定・主張(light assertion).)

