Ako by sa preložila táto veta :

My family and I are going to do some days trips to nearby villages in our local countryside.

… niekoľko jednodenných výletov …

alebo

… niekoľkodenné výlety …

Ďakujem.

… niekoľko jednodenných výletov … = some day trips (not days trips).

The explanation is that „day“ is functioning here as an adjective (not a noun): what kind of trips? Day trips, not cycling trips or coach trips. Adjectives don't pluralise, so: some green apples (not some greens apples). 🙂

… niekoľkodenné výlety … = some several-day trips or some trips lasting several days

Thank you for your answer, Dan. However, the problem here was the expression : " some days trips. "

The sentence had been written by an English teacher as an example sentence. I couldn´t puzzle out the construction and this was why I was asking. They must have made a mistake/a typo.

Přidávám pro jistotu odkaz na článek věnující se této problematice:
Dvoudenní, tříměsíční, desetiletý…

Ďakujem pekne za článok.

Ak by to bol ten druhý typ – pomocou privlastňovacieho pádu – tak v príkladovej vete chýbal apostrof a význam by bol niekoľkodenné výlety.

… some days' trips …

The original sentence („My family and I are going to do some days trips to nearby villages in our local countryside“) is grammatically incorrect, so it's impossible to say what it means.

My guess (because they're going to nearby villages) is that the trips will take one day. So they're going to do (some) (one-)day trips.

„Some days' trips“ (with the apostrophe) is also grammatically incorrect. ☹️

… niekoľkodenné výlety…= (some) several-day trips or (some) trips lasting several days. (As I said in my first answer 😉 )

Aj keď každý deň makáme na tom, aby sme mohli byť o niečo lepší ako včera, vieme si nájsť čas aj na zábavu. Po práci organizujeme akcie rôzneho druhu: od firemných party a udalosti pre verejnosť, až po niekoľkodenné výlety – napríklad za alpským snehom. (mergado.sk)

After work we organise various different events from company parties and events for the public to several-day trips (away) – for example to the Alps for snow activities.

But I am still not sure, as

TWO DAYS' JOURNEY (dvojdenná cesta) – correct

SOME DAYS' TRIP – (niekoľkodenný výlet) – incorrect

Why ? It seems to be exactly the same expression.

Thank you very much.

The problem is that these two three-word phrases with the same punctuation have been taken out of context, but their syntax is different.

In any case, „some days' trip“ is impossible because „some“, whether it's the strong stressed /sʌm/ or the weak unstressed /səm/, doesn't convey the sense of několik (or více) here, which is several, not nějaké or některé.

Two days' journey is a kolik čeho? (dva dny cestování) construction (like four hours' sleep, three hours' drive, two weeks' holiday) not a jaké co construction like a several-day trip, a four-hour sleep, a three-hour drive. or a two-week holiday. So

• I had four hours' sleep on the plane. (kolik čeho?)
• I had a four-hour sleep on the plane. (jaké co?)
• I had a four-hours' sleep on the plane. (kolik co?)
• It's three hours' drive from Ostrava to Bratislava.
• It's a three-hour drive from Ostrava to Bratislava.
• It's a three-hours' drive from Ostrava to Bratislava.

• We're going on several days' holiday to the Alps.
• We're going on a several-day holiday to the Alps.
• We're going on a several days' trip/holiday to the Alps.

• We're going on some days' holiday to the Alps.
• We're going on a some days' holiday to the Alps.

In the last two sentences. the problem is „some“, which doesn't convey the idea of několikadenní/ví­cedenní.

Now I got it. SOME does not mean SEVERAL here. I just need to figure out where the difference is. I have always thought they both mean the quantity. Thank you, Dan.