question: Charlie has boots that are five times the size of Sophie's. If Sophie wears size five boots, what is the average size of shoe worn by the two?
answer: If Sophie wears size five shoes, Charlie wears 5 * shoe size 5 = shoe size <<5*5=25>>25
  Their combined shoes size for the two is shoe size 25 + shoe size 5 = <<25+5=30>>30
  The average for the shoe size the two wear is shoe size 30/2 = shoe size <<30/2=15>>15
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