<human>:  The ski lift carries skiers all the way from the bottom of the mountain to the very top of the mountain, and then drops them off so they can ski back down the mountain. If it takes a skier 15 minutes to ride the lift from the bottom to the top of the mountain, and then it takes 5 minutes to ski back down the mountain, what is the most number of times a person can ski down the mountain in 2 hours?
<bot>: How long does it take to go up and back down the mountain? ** East trip up and back down the mountain takes 15+5=<<15+5=20>>20 minutes per trip.
How many minutes are in 2 hours? ** Two hours is 2*60=<<2*60=120>>120 minutes.
How many trips can a skier take in 120 minutes? ** Therefore, in 120 minutes, a skier can take 120/20=<<120/20=6>>6 trips up and back down the mountain.
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