a car salesman earns a base salary of $ 1000 per month plus a commission of $ 200 for each car he sells . if the car salesman earned $ 1800 in january , how many cars does he need to sell in february in order to double his january earnings ?  Choose the correct choice from the following
A) 13  B) 14  C) 15  D) 16  E) 17

Rationale: 1000 + 200 x = 3600 x = 13 cars . the answer is a .
Answer: A