conversations.from: human
conversations.value: Lenny bought 20 boxes of pens. Each box contained  5 pens. She gave 40% of the pens to her close friends and one-fourth of what's left to her classmates. How many pens were left for Lenny?
conversations.from: assistant
conversations.value: Lenny has 20 x 5 = 100 pens.
  She gave her close friends 100 x 40% = 40 pens.
  So, 100 - 40 = 60 pens were left.
  Half of 60 is 60/4= 15 pens.
  Thus, Lenny has 60 - 15 = 45 pens left.