conversations.from: human
conversations.value: Tire repair for each tire costs $7, plus another 50 cents for sales tax. If Juan needs all 4 tires repaired, how much is the final cost?
  Give me a solution to this problem
conversations.from: assistant
conversations.value: Juan pays 4*7 = 28 dollars for all four tire repairs.
  Juan pays 0.50*4 = 2 dollars in sales tax for all four tire repairs.
  Juan pays a total of 28+2 = 30 dollars.