用一根绳子测量井深,直接量,井外余⑤米.对折量,离井口还差4米.井深几米?绳子长几米?

用一根绳子测量井深,直接量,井外余⑤米.对折量,离井口还差4米.井深几米?绳子长几米?
用一根绳子测量井深,直接量,井外余⑤米.对折量,离井口还差4米.井深几米?绳子长几米?

用一根绳子测量井深,直接量,井外余⑤米.对折量,离井口还差4米.井深几米?绳子长几米?
x=y+5
x/2=y-4
x/2=9
x=18
y=13
井深13米,绳子长18米

绳子长18米,井深13米