Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
There are 3 workers producing chairs in a furniture factory. Each of them produces 4 chairs an hour. As a group, they produce an additional chair every 6 hours. In total, how many chairs have been produced after 6 hours?

### Response:
Each worker produces 4 chairs an hour, so altogether they produce 3*4=<<3*4=12>>12 chairs an hour.
In addition, they produce an additional chair every 6 hours, so they produce an additional chair every 6/12=<<6/12=.5>>.5 hours.
After 6 hours, they produce a total of 12 + 6/12 = <<12+6/12=12.5>>12.5 chairs.
#### 12.5

