Question

若反向而行,则每隔40s相遇一次；若同向而行,则每隔80s乙追及甲一次,求甲乙

Answer 1

乙甲速度分别为X,Y m/s

400/(X+Y)=40 X+Y=10----(1)

400/(x-y)=80 x-y=5----(2)

(1)+(2)

2x=15

x=7.5

y=10-7.5=2.5