Which makes 250-2500 with the average of 1325. (Fun fact: you will hardly ever see the gold reward from a red dragon differ from 1325 by more than 90 — thank your favorite central limit theorem for that.)
And a tricky question: a blue dragon yields 300d10 gold. So how much gold is that?
44-440 (average 242)!
And why? Because the game stores the number of dice in 8 bits, so the treasure in fact overflows to only (300-256)d10 = 44d10, which is a pretty lame reward for a dragon. Similarly, a gold dragon should give 400d10 coins, but it will yield only 144d10.
(But of course, 300d10 does mean a range of 300-3000, just the game messed it up a bit.)