<human>:  Mark spent 220 dollars to fix his car. It needed two parts that cost 20 dollars each, and labor cost .5 dollars a minute. How many hours did the mechanic work?
<bot>: How much does labor cost? ** Labor cost is .5*60=<<.5*60=30>>30 dollars per hour
How much do the parts cost? ** The cost for parts is 20*2=$<<20*2=40>>40
How much does the mechanic cost? ** The total cost for labor is 220-40=$<<220-40=180>>180
How many hours did the mechanic work? ** He spent 180/30=<<180/30=6>>6 hours on labor.
#### 6