human
James hires a horse-drawn carriage from 5 PM to 9 PM. He gets 1 hour free. The first paid hour is $15 and each hour after that is twice the cost. How much did he pay?
assistant
How many hours did he get for free? ** He got it for 9-5=<<9-5=4>>4 hours
How many hours did he pay for? ** He pays for 4-1=<<4-1=3>>3 hours
How much did the first hour cost? ** The first hour cost 1*15=$<<1*15=15>>15
How much did the other hours cost? ** The other 3-1=2 hours are more expensive
How much did the other hours cost? ** They cost 15*2=$<<15*2=30>>30 per hour
How much did the other hours cost? ** So those 2 hours cost 2*30=$<<2*30=60>>60
How much did he pay? ** So he pays 60+15=$<<60+15=75>>75 per hours
#### 75