technically, Ręka means Arm, Hand would be Dłoń. though in polish it's common for ręka to be used when talking about hands (like when you "shake hands", in polish you "shake arms", or ask for someone's arm in marriage instead of their hand), dłoń would be a more accurate translation
it depends on where you are, in some English-speaking places it's exactly what you say it's like, but in some other places, they use dinner/supper instead of lunch/dinner
Great quiz
Idk what to say