As I already said, the context was set in the previous sentence: “Suppose you make $10,000 a year”. So we’re talking about annual salary. If you’re going to change that context, then you need to give the reader a clue that you’re doing so. Especially in a “puzzle” like this. That’s not redundant, it’s required for clarity.
The people arguing that the $300 is better have doubled the $300 twice. Once because they say you’ll get it twice a year and another time because in their minds the $300 is an increase in your semiannual pay rate so to convert it into your annual pay rate you need to double it.
The people arguing against this (myself included) are pointing out that the question never says the $300 is an increase in your semiannual pay rate or that the $1000 is an increase in your annual pay rate. But it’s sensible to assume they both mean annual pay rate (salary) because that’s how pay is measured.
I agree that a $300 semiannual raise is better than an annual $1,000 dollar raise. I sat down and did all the calculations myself exactly as the word problem specified and indeed got two very different answers. Maybe the question could be worded differently or better, but that’s not what I want to ask about.
What I want to know is how in the hell the semiannual raise winds up being higher than the annual raise! It does, I tried it. But I can’t for the life of me figure out why 300 dollars twice a year doesn’t add up to 600 dollars a year. There’s not a fraction in there. It’s not a 10% raise or anything. I feel really dumb.