In all fairness, one could write: juna kaj kune. as well, no ?
Looking at one of the other answers by James T. Wilson, I think it was implied that there are two (hence the "together"). So "junaj kaj kune" may have worked but not "juna kaj kune".
I was docked for saying "Juna" what causes us to need to say "June"?
I would say "june" ought to mean "youthfully." I wrote "juna" and do realize that I probably should have written "junaj," since I did take both words to refer to the same things.
I don't understand this sentence...
It's the slogan of TEJO.
So, what do they take that word to mean? I must admit that I simply cannot accept the idea of "young" as an adverb in English.
Try "in a young/youthful way," as for example to see things with fresh eyes.
[Ni ekzistas] june kaj kune? Eble?
Mi estas june, sed mi estas maljuna.
I am youthful, but I am old. This is not a contradiction.
*Mi estas juneca, sed mi estas maljuna.
So we'll set the world on fire....