Answer:
333 cars
Explanation:
Assuming among 6 agents, the working efficiency is the same and constant. Fixing number of agents:
6 agents can sell 333 cars in 3 months.
=> 6 agents can sell 333/3 cars in 3/3 month.
=> 6 agents can sell 111 cars in 1 month.
Fixing number of months:
=> 6/2 agents can sell 111/2 cars in 1 month.
=> 3 agents can sell 111/2 cars in 1 month.
Then considering that 3 agents worked in 6 months:
=> 3 agents can sell 6 x 111/2 cars in 6 x 1 months.
=> 3 agents can sell 333 cars in 6 months.