conversations.from: human
conversations.value: James wants to build a 16-foot by 20-foot quilt.  He uses patches that are each 4 square feet.  The first 10 patches cost $10 each and then each patch after that cost half as much.  How much do the patches for the quilt cost?
  Give me a solution to this problem
conversations.from: assistant
conversations.value: The patch is 16*20=320 square feet
  So he needs 320/4=80 patches
  The first 10 patches cost 10*10=$100
  He gets a discount on the next 80-10=70 patches
  They each cost 10/2=$5
  So in total they cost 70*5=$350
  That means in total he paid 100+350=$450