I got stuck on this one too so I'll reply:
The key thing is here to read carefully: Of those who answered "Yes" to the first question, 785 answered "Yes" to the second question, and 380 answered "No" to the second question.
Basically this is saying 785 + 380 = 1170 is what people said "Yes" to the first question. Given we know the "Yes" now and 1,455 of total participants, we can figure out the number of "No" for the 1st question which is 290.
Now it's asking us what happened to the 290 so we know that x + y must equals 290 and x>y so we are just looking for two values that add up to 290. Hope that helps