conversations.from: human
conversations.value: Carl buys index cards for his class.  He gives each student 10 index cards.  He teaches 6 periods a day and each class has 30 students.  If a 50 pack of index cards cost $3 how much did he spend on them all?
  Can you solve this problem?
conversations.from: assistant
conversations.value: He has 30*6=180 students
  So he needs to buy 180*10=1800 index cards
  That means he needs to buy 1800/50=36 packs of index cards
  So he spends 36*3=$108