一根电线截去4/1后再接上12米,结果比原来长3/1.这根电线原长多少米?
问题描述:
一根电线截去4/1后再接上12米,结果比原来长3/1.这根电线原长多少米?
答
12÷(1/3-1/4)
=12÷1/12
=144米
答原长144米