Al and Bill live at opposite ends of the same street. Al had to deliver a parcel to Bill’s home, Bill one at Al’s home. They started at the same moment, each walked at constant speed and returned home immediately after leaving the parcel at its destination. They met the first time at a distance of a yards from Al’s home and the second time at a distance of b yards from Bill’s home.

Question

Al and Bill live at opposite ends of the same street. Al had to deliver a parcel to Bill’s home, Bill one at Al’s home. They started at the same moment, each walked at constant speed and returned home immediately after leaving the parcel at its destination. They met the first time at a distance of a yards from Al’s home and the second time at a distance of b yards from Bill’s home. 
Assume that Al and Bill walk less than twice as fast as each other.

I answered the question above but the second part is this and I don't know how to solve this:

How should we change the four equations we use to describe the prob- lem if Al walks more than twice as fast as Bill?

bobpursley · Answer

Twice as fast mean Al will be back home (there and back) when Bill reaches Al's end (ie, they both get there at the same time. That is the second time they meet, the first was at 2/3 the way from Al to Bill's end.