"How strong is the wind?"
だれくらい is an adverb phrase meaning how long, how far, how much, it could be used to ask for the degree, the extent, the amount. here the speaker is questioning about 強い(つよい), the intensity of the wind
So it should be dono instead of dore, because the example asks how strong the wind is.
That's an amount.
Japanese consider an amount as someting quantitative. While you can measure the speed of the wind in m/s, the answer to the question here is an opinion like: "Yes, it is strong." or "No, it isn't strong."
Therefore, you would use どれくらい for asking a qualitative question like this one, and どのくらい for a quantitative question like "What is the strength of the wind in m/s right now." Hope I was of help!
I may be wrong but i'd always assumed どの was the more polite way of saying it, like どこ vs どちら. (The latter being more polite)
You're right. Maybe if we all report each case of this happening, they'll fix it faster. They've fixed a lot of stuff since they first opened these lessons for Japanese. It's still a new language in duolingo in comparison to others.
Whoa. What i CAN interpret from this makes so little sense that I can't even guess the rest from context.