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

### Instruction:
Betty bought 1 kg of oranges and 3 kg of apples. The total cost of oranges was $12. The apples were two times cheaper than the oranges. How much did Betty pay for 1 kg of apples?

### Response:
 เบตตี้จ่าย 12 * 0.5 = 6 ดอลลาร์สำหรับแอปเปิ้ล
ดังนั้นราคาของแอปเปิ้ล 1 กิโลกรัมคือ 6 / 3 = 2 ดอลลาร์