What does「十分になるか、ならないか」mean?

Question

Currently reading こころ 四話

「たった今出たばかりで、十分になるか、ならないかでございます」と奥さんは気の毒そうにいってくれた。

Does the bold part mean the same thing as「十分になるかもしれません」? How this phrase works?

Answer 1

The meaning of 十分になるかもしれません Possibly ten mins have passed may be not that different from the bold phrase, but it is more interchangeable with 十分くらいです It is about ten mins.

Generally Xになるかならないか where X contains some quantity means (the amount) reaches X or possibly less. In the example, the amount is the time that has passed since someone (husband?) left home, and she is saying it is 10±α mins.

Some other examples:

• 私が10歳になるかならないかのとき When I was around 10 years old
• このパソコンは5万するかしないかだった This PC costed 50000 yen or maybe less
• 今年のボーナスは100万いくかいかないかくらいだ This year's bonus will be around 1000000 yen

The pattern has a nuance of at most (around) X, which should be the difference from the other expressions mentioned above.

Answer 2

After Chocolate explained it to me, I'll try and give a better answer.

The bolded part is still an embedded question. The quoted sentence means:

It just came out. It will be about 10 minutes.

Here, using かもしれません changes the meaning quite drastically: it now means "It might be ten minutes".

Edit: in response to Nanigashi's comment, the quoted sentence would mean:

He just left, about 10 minutes ago.