"Are you going or not?"
Translation:Ви ідете чи ні?
«Ти бу́деш чи ні?» (not «не») is a question about the future with the main word omited: the verb is understood from the context. It could theoretically mean going, if «ти б́у́деш іти́ чи ні» is assumed (i.e. if the verb іти́ was used before), but Duolingo doesn't usually allow sentences with parts of them omited because, well, any part of the sentence could be omited in a dialogue.
«Ти бу́деш [verb omited] чи ні?» could be used as a translation of 'Are you going to [verb omited] or not', i.e. when 'going' is not a main verb denoting movement, but a auxillary verb to show that the action is to happen in the future.
I'm confused - should all їдете, йдете and ідете be accepted in 'Ви _дете чи нi?' or this is a technical glitch in Duo?
PS Just for clarification - the first two options are given as correct translations in the multiple choice question and the final one is given as a translation in the comment section.