"How are you? And how are you?"
Translation:तुम कैसे हो? और तुम कैसी हो?
I wrote आप कैसे हैं? और तुम कैसी हो? the first being formal and latter casual. It was rejected! I imagined a scenario where you would greet a grandfather and his grandchild.
This time around I tried to have both sentences in the formal address आप कैसे हैं? और आप कैसे हैं? and I was corrected with आप कैसे हो? और आप कैसे हो which confused me completely. I had learned (long ago) that when you use the formal आप you end it with the formal हैं, and vice versa, if you use तुम it becomes हो. But I have never seen the combination where आप has the ending of हो. It can either be आप कैसे हैं? or तुम कैसे हो?, not mixed, right?
I've added all the possible translations now. Regarding the confusion, while "आप कैसे हैं" is technically more correct and would be used in formal settings, the majority of native speakers use "आप कैसे हो" as well, and it conveys a slightly different tone than the former, being more intimate while still respectful. For instance, I use the former with complete strangers or my teachers, while the latter at home with elder family members. We are accepting this form because it is very widely used by almost everyone, but we're not explicitly teaching it in the course because it's more of a colloquialism. I had still not added all the correct translations then, so that is why it corrected you and showed you this other.
You and the others have done a truly awesome job on this course! I have followed it from the start and it was worth the long wait. Very high quality indeed :)