Chester must deliver ten bales of hay to Farmer Brown. Farmer Brown wants Chester to supply better quality hay and double the delivery of bales of hay. If the previous hay cost $15 per bale, and the better quality one cost $18 per bale, how much more money will Farmer Brown need to meet his own new requirements? Let's think first. Chain of thought:
The hay previously cost $15 per bale so 10 bales would cost $15 * 10 = $150. Double 10 bales is 10 * 2 = 20 bales. Better quality hay cost $18 per bale so 20 bales would cost $18 * 20 = $360. Farmer Brown would need $360 - $150 = $210 more.
Therefore, the answer is 210.