question: James decides to pick some blueberries.  It cost $20 to go picking and then another $1.5 per pound.  He picked 30 pounds of blueberries.  How much did he save compared to buying at the store for $2.5 a pound?
answer: He paid 30*1.5=$<<30*1.5=45>>45 for the blueberries he picked
  So after the entrance fee it was 45+20=$<<45+20=65>>65
  To buy them at the grocery store it would cost 30*2.5=$<<30*2.5=75>>75
  So he saved 75-65=$<<75-65=10>>10
  #### 10