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

### Instruction:
Marcus, Humphrey, and Darrel are bird watching. Marcus sees 7 birds, Humphrey sees 11 birds, and Darrel sees 9 birds. How many birds does each of them see on average?

### Response:
 ทั้งหมดพวกเขาเห็นนก 7+11+9 = <<7+11+9=27>>27 ตัว
เฉลี่ยพวกเขาเห็นนก 27/3 = <<27/3=9>>9 ตัวต่อคน