prompt: Ben's new car cost twice as much as his old car. He sold his old car for $1800 and used that to pay off some of the cost of his new car. He still owes another $2000 on his new car. How much did his old car cost, in dollars?
messages.content: Ben's new car cost twice as much as his old car. He sold his old car for $1800 and used that to pay off some of the cost of his new car. He still owes another $2000 on his new car. How much did his old car cost, in dollars?
messages.role: user
messages.content: His new car costs 1800+2000=<<1800+2000=3800>>3800 dollars.
  His old car cost 3800/2=<<3800/2=1900>>1900 dollars.
  #### 1900
messages.role: assistant