I've checked online but I can't seem to find a proper explanation on how かは is being used here. Individually, I know they mean (か = question marker, は = topic Marker). I've rechecked the source book (An Integrated Approach To Intermediate Japanese) countless times to make sure it wasn't a typo either.
Is it asking a question and marking the whole thing in implied quotes using は? Like how I can say "'Are you there?', asked Bob?"
Or am I completely off in my interpretation?
Edit: It was brought to my attention that I made a mistake. Originally I had 難しいが when instead it should've been 難しいか. Thank you to senshin and BurakUeda for pointing that out.