conversations.from: human
conversations.value: Maci is planning for the new school year and goes to the store to buy pens. She needs ten blue pens and 15 red pens. If a blue pen costs ten cents each and a red pen costs twice as much as the blue pen, how much money does Maci pay for the pens?
  Give me a clear explanation.
conversations.from: assistant
conversations.value: Maci pays 10 * $0.10 = $1 for the blue pens.
  Each red pen costs 2*$0.10 = $0.20
  She pays 15*$0.20 = $3.00 for the red pens.
  To buy all the pens she needs, Maci pays $3+$1= $4