How Do Two Cyclists Traveling Towards Each Other Meet?

[blooreema]

I tried for a really long time to try to answer this question, but I keep getting weird answers... could someone try and help me out? I know we're supposed to use the substitution method but I don't quite get how...


Vectorville and Scalartown are 20.0 km apart.
A cyclist leaves Vectorville and heads for Scalartown at 20.0 km/h.
A second cyclist leaves Scalartown for Vectorville at exactly the same time at a speed of 15.0 km/h.

a) Where will the two cyclists meet between the two towns?
b) How much time passes before they meet (in minutes)?

 

[lavalamp]

I'm not really sure what you mean by the substitution method, if you were to explain what you mean by that maybe I could give you a pointer as to how to calculate the answer that way.

However, the way I would do it would be to realize that the two bikes could be treated as one bike traveling at 35 Km/h for a distance of 20 Km. Using good old speed = distance / time would give you the answer to part b, then you could use that to calculate the answer to part a.