I have been reading an article and I came across a sentence:
South Korean YouTuber Sw Yoon decided to conduct a little experiment around the campus of Ritsumeikan Asia Pacific University in Japan. He asked a bunch of students, all from different countries around the world, how could they could recognize Americans.
I'm wondering why the word "could" is used twice in this sentence? I think it would be correct too if it were like this:
how could they recognize Americans.