question: There are 90 rooms at the KozyInn Motel. It takes housekeeping 20 minutes to clean each room. How many hours would it take to clean one-half of the rooms?
answer: 90 * 20 = <<90*20=1800>>1800 minutes
  1800/2 = <<1800/2=900>>900 minutes
  900 minutes = <<900/60=15>>15 hours
  It would take 15 hours to clean 45 rooms at the KozyInn Motel.
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