question: Eve had 20 pieces of pomelos. After giving her friend some pomelos, Eve is left with 1/4 of the pomelos she originally had. How many pomelos did Eve give away?
answer: Eve is left with 20 x 1/4 = <<20*1/4=5>>5 pieces of pomelos.
  So she gave away 20 - 5 = <<20-5=15>>15 pieces of pomelos to her friend.
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