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

### Instruction:
 James wants to build a 16-foot by 20-foot quilt. He uses patches that are each 4 square feet. The first 10 patches cost $10 each and then each patch after that cost half as much. How much do the patches for the quilt cost?


### Response:
 Le nombre de patches est de 16*20/4 = <<16*20/4=160>>160.
Les 10 premiers patches coûtent 10*10 = <<10*10=100>>100 dollars.
Les 150 patches restants coûtent 100/2 = <<100/2=50>>50 dollars.
Donc le coût total est de 100+50 = <<100+50=150>>150 dollars.