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

### Instruction:
Tom decided to go on a trip. During this trip, he needs to cross a lake, which in one direction takes 4 hours. During this time, Tom needs an assistant to help him with the crossing. Hiring an assistant costs $10 per hour. How much would Tom have to pay for help with crossing the lake back and forth?

### Response:
 การข้ามทะเลสาบสองครั้ง (ไป-กลับ) จะใช้เวลา 4 * 2 = <<4*2=8>>8 ชั่วโมง
ดังนั้นทอมจะต้องจ่ายเงินให้ผู้ช่วย 8 * 10 = $<<8*10=80>>80.