Amy left 1 hour early then TJ to mom but Amy drove 80 kph and TJ drove 100kph. At what point did TJ pass Amy?

Question

this is one of those distance= time x speed word problems
the answer is 400 km but i need to know how to get it

Answer 1

First make equations for their distances traveled:

Da = 80x + 80

Dtj = 100x

Then set them equal to each other:

80x + 80 = 100x

80 = 20x

x = 4 hr

As a result, we found the time at which they meet, and one passes another. Now we plug in that time into any one of the distance equations to find the distance at which one passes another:

Djt = 100x

Djt @ 4 hrs = 100(4) = 400km

Answer 2

you gotto gotto gotto know the way

your not ever going to need that when you grow up