conversations.from: human
conversations.value: I'm completely lost with this math problem: Mitch has saved $20000 to finance his boating hobby. A new boat costs $1500 per foot in length. If Mitch needs to keep $500 for a license and registration, and three times that amount for docking fees, how many feet is the longest boat he can buy?
  Can you give me a hand?
conversations.from: assistant
conversations.value: Mitch needs to keep 500 * 3 = 1500 for docking fees.
  Thus, he needs to keep 500 + 3 * 500 = $2000 for license, registration, and docking fees.
  He has 20000 - 2000 = $18000 left to spend on a boat.
  Therefore, the longest boat he can buy is 18000 / 1500 = 12 feet long.