The question about the time Lin complete the race. This is just my 2 cent thought;


Mei speed is 20km/hr
Lin is always 3.5km behind Mei.

In 1 hr, Mei would travel 20km
And Lin would travel 20-3.5=16.5km
So the speed of Lin is 16.5km/hr

We only need to know the how much faster is Mei to Lin and add the diff to the Mei’s arrival time.

Sound logical, can someone tell me if I’m right.