黄河全长约5500km,比长江全长的2/3多1300km,那么长江全长约多少千米?

问题描述:

黄河全长约5500km,比长江全长的2/3多1300km,那么长江全长约多少千米?

5500-2/3x=1300
2/3x=4200
x=6300km