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

### Instruction:
Tony has $87. He needs to buy some cheese, which costs $7 a pound and a pound of beef that costs $5 a pound. After buying the beef and his cheese, he has $61 left. How many pounds of cheese did he buy?

### Response:
 เขาใช้เงิน 26 เหรียญ เพราะ 87 - 61 = <<87-61=26>>26
เขาใช้เงิน 21 เหรียญ สำหรับเนย เพราะ 26 - 5 = <<26-5=21>>21
เขาซื้อเนย 3 ปอนด์ เพราะ 21 / 7 = <<21/7=3>>3