Runner A is initially 5.3 km west of a flagpole and is running with a constant velocity of 8.1 km/h due east. Runner B is initially 4.7 km east of the flagpole and is running with a constant velocity of 7.8 km/h due west. How far are the runners from the flagpole when their paths crossed? answer in units of km
Xa = -5.3 + 8.1 t
Xb = 4.7 - 7.8 t
so when they meet Xa=Xb
-5.3 + 8.1 t = 4.7 - 7.8 t
15.9 t = 10
so
t = 10/15.9
then Xa = x for example
= -5.3 + 8.1(10/15.9)