Translation:He used to find solutions to all the problems.
Well, Spanish speakers do often leave off the "s" in words, but the Duolingo voice is usually made to pronounce everything and enunciate, so, yeah, I would report it.
However, hopefully one day you will get to the point where you will be able to hear something said very unclearly in Spanish and your brain will fill in the gaps and correct it automatically like it does in English (assuming you are a native English speaker). A native Spanish speaker would probably know to write the "s" even if they didn't hear it because the sentence would not make sense with an "s" on "los problemas" but not on "todos".
Problemas is masculine. While words ending in "a" are overwhelmingly feminine in Spanish, ones ending in "ema" or "ama" are very often masculine and an exception to the overall rule.
I vaguely recall my high school Spanish teacher saying that's because they came from Greek.
Hola kerkeslager: Here are a couple of sites that will start you on a list of nouns in each gender and the exceptions. I put them both into a Word document and keep adding ones I want to remember as I run into them. There is just too much to remember in my overworked brain.
3rd person imperfect; it's in there I think, under "more tenses" or some such: check http://www.studyspanish.com/lessons/pretimp1.htm and all of that unit on preterite vs imperfect, adna also http://en.wiktionary.org/wiki/encontrar.
I think "he used to find" and "he was finding" are kinda the same, according to what I've found, no?
I disagree: "he was finding solutions' is a permissible translation of the imperfect as is "he used to find solutions". "He found solutions" is also possible. The first two translations are specific to the imperfect while the third might represent a translation of the preterite or the imperfect.IMHO
One can distinguish between being in the process of finding ('was finding') versus having completed this process ('found'). is 'encontraba' ambiguous in this regard? For example, 'I was finding my way through the maze.' is different from 'I found my way through the maze.'
Having now read this: http://spanish.about.com/od/conjugation/a/conjugation_imperfect.htm it seems the answer is yes, it depends on context.