Q: A merchant bought 15 keyboards and 25 printers for a total of $2050. If a keyboard costs $20, how much does a printer cost?
A: 15 keyboards at $20 per keyboard cost a total of 15 * $20 = $300. The total cost of printers and keyboards is $2050 so 25 printers cost $2050 - $300 = $1750. 1 printer cost $1750 / 25 = $70. The answer is 70.

Q: Colton had 72 dolphin stickers. He gave 4 stickers each to 3 friends. He also gave his friend Mandy 2 more than he gave his three friends total.  And he gave Justin 10 less than Mandy. How many stickers does Colton have left?
A: Colton gave away 4 stickers * 3 friends = 12 stickers. Colton gave Mandy 2 + 12 stickers = 14 stickers. Colton gave Justin 14 stickers - 10 = 4 stickers. In total, Colton gave away 12 + 14 + 4 stickers = 30 stickers. Colton's number of total stickers at the end is 72 - 30 = 42 stickers. The answer is 42.

Q: James binges on Cheezits and eats 3 bags that are 2 ounces each. There are 150 calories in an ounce of Cheezits. He then goes for a 40-minute run and burns 12 calories per minute. How many excess calories did he eat?
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
He ate 2 * 3 = 6 ounces of cheez its. That means he ate 6 * 150 = 900 calories. He burned 40 * 12 = 480 calories. So he ate an excess of 900 - 480 = 420 calories. The answer is 420.