一根绳子截去20%后,再接上6米,结果比原来的绳子还长30%,这根绳子原来多少米?

问题描述:

一根绳子截去20%后,再接上6米,结果比原来的绳子还长30%,这根绳子原来多少米?

6÷[(1+30%)-(1-20%)]
=6÷(130%-80%),
=6÷50%,
=12(米).
答:原来有12米.