Translation:This week, I will go to the pool with him.
either way doesnt matter. in japanese there is no "the" or "a" because thats not important unless otherwise explained. both should be excepted unless it just sounds plain wrong in english.
と means both "and" and "with" as it is a particle that shows involvement. といっしょに specifically means "together with"
I think there is no problem with that. I also tried to add "together", because duolingo has marked so many other questions wrong if I leave out "together" when "issho ni" is present. It seems there is a vast amount of inconsistency with regard to this in the program at the moment.
I guess you could report it since it's <sub>technically</sub> a good translation, but I think the sentence is more along the lines of, "He is going to the pool, so I am going with him because I am accompanying him." (e.g. It was most likely HIS plan to go to the pool and I am just tagging along.) But I may be wrong about that. The sentence doesn't really say, "He and I", it says "(understood "I") go with him", as far as I understand. If that makes sense.
The japanese sentence should be 「今週、かれとプールに行きます。」since it doesn't accept any of these: This week, he and I will go to the pool together. / This week, I will go to the pool together with him. / This week, we will go to the pool together. / This week, we will go together to the pool. / This week, I will go to a pool together with him.
There are a few ways to pronounce the same kanji based on context, usually when "今 " is alone it's pronounced "ima" and when paired with something like 今週 its "kon" and then you have have examples like 今日 when its neither. Other examples of words you already know that do this are 日-which can be ni, hi and bi depending on context/pairings; 水 which could be mizu alone or sui in the case of 水曜日 (suiyoubi); 愛 which is usually ai but also koi and 一 ichi, or hi depending on whether or not you're counting things. In school they explained it as Chinese root/origin word versus Japanese adaption/native words
It's "issho" rather than "ishaa" and it means "together", https://jisho.org/search/together.
[かれ] = him, [かれと] = with him, [かれといっしょに] = together with him.
What I'm not sure of is what @AndyCardoso23 posted a few days ago; is "issho" required, is it just helpful for providing context, or is [かれとプールに行きます] alone sufficient?
is there a way to report these audio questions (when you listen to the audio and have to type the answer in japanese)? they are so random regarding the way you write your answer... if you write everything in kanji it will mark it as wrong because some words should be in kana, so i started writing everything in kana and now it marks it as wrong because some words should be in kanji. basically, i have to guess which words duo wants in kanji or kana.