human
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?
assistant
How much did Ben's new car cost? ** His new car costs 1800+2000=<<1800+2000=3800>>3800 dollars.
How much did Ben's old car cost? ** His old car cost 3800/2=<<3800/2=1900>>1900 dollars.
#### 1900