Runner A is initially 5.3km west of a flagpole and is running with a constant velocity of 8.8km/hr due east. Runner B is initially 4.2km east of the flagpole and is running with a constant velocity of 7.9km/hr due west. How far are the runners from the flagpole when their paths cross in units of km?

Question

Runner A is initially 5.3km west of a flagpole and is running with a constant velocity of 8.8km/hr due east.  Runner B is initially 4.2km east of the flagpole and is running with a constant velocity of 7.9km/hr due west.  How far are the runners from the flagpole when their paths cross in units of km?

Henry · Answer

d1 + d2 = 5.3+4.2 = 9.5 km = Distance
between the runners.

8.8t + 7.9t = 9.5
16.7t = 9.5
t = 0.569 h. to cross paths.

d1 = 5.3 - 8.8*0.569 = 0.293 km West of flagpole.

d2 = 4.2 - 7.9*0.569 = -0.295 km West of
Flagpole.

So they meet at approximately 0.294 km
west of flagpole.