Question

用绳子测试井深,打三折来量,井外余4米,打四折,井外余1米.求绳长和井深?

Answer 1

设绳子长x

x/3 -4=x/4-1

x/3-x/4=4-1

x/12=3

x=36

井深 36/3-4＝12-4＝8m