this is a hard question!!

Question

Erica and amy start biking in the opposite direction at the same time. eric picked at a speed of 6 meters and amy picked at a speed of 4 meters per second. how soon were they exactly 1 km apart?

Answer 1

Suppose they both travel for a time t (seconds) in opposite directions.  Then Erica travels a distance 6t (meters) while Amy travels a distance 4t (meters).  The 2 distances must add up to the separation distance of 1 km = 1000 m.

 

6t + 4t = 1000

 

t = 1000/(6 + 4) s = 100 s