# ChatGPT／t5／3回目／2026-09-29
# モデル表示: 中程度／所要 26.7秒／264文字
# 採点: 正解（URL 3/3本が実在／マイル換算 ○（正解20.92)）

答え: 20.92
https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8

https://www.nist.gov/pml/us-surveyfoot/revised-unit-conversion-factors

https://nvlpubs.nist.gov/nistpubs/hb/2013/NIST.HB.133-2014.pdf