Work and Rates ( distance )

[Abdulla]

I'm confused with two things:

When the traveler travel towards each other why sometimes we equal the two equations together ad solve and the other time we add the two distance and = to the total distance.
i.e
R1= 240 T1= t+10 min. Total Dis=300
R2=160 T2 = t

Rephrasing my question : why we did 240 (t+1/6)+ 160t = 300 rather than
240(t+1/6)=160t and solve ..

When I have to use either way?

[Jade3]

The first equation explains a situation, where both travelers meet at a point and the distance between two points is 300 Km. The second equation is incorrect as 240(t+1/6) cannot equal 160t, unless t is negative and we know that time cannot take negative values

[JonathanSchneider]

Well explained, Jade.