"After you have a shower, you have coffee."
Translation:Ar ôl i chi gael cawod, dych chi'n cael coffi.
Ar ôl I chi ............rwy ti.......... Why mix up chi and ti in same sentence? Yet this was marked as correct.
Why did you input an incorrect sentence, then?
As for the technical reason why it was accepted: it's easier for a course contributor to say that an acceptable version is "Ar ôl i [ti/chi/chdi] gael cawod, [dych chi/dach chi/wyt ti]'n cael coffi" or the like with alternatives, rather than making two separate sentences, one for "chi" and one for "ti" to make sure that the two parts will use the same form. (Though doing so would be "cleaner".)
It can work. After you (pl.) have a shower, you (sing.) have coffee makes sense for the same reason that After we have a shower, I have coffee makes sense.
It is multiple choice and you have to mark all correct answers. And these ti/chi mixtures always show up. As balbhan explained it can make sense, but not at the first view.