Problema Solution

Rob left the movie theater and traveled west at an average speed of 20 km/h. Imani left some time later travelingin the same direction at an average speed of 30 km/h. After traveling for two hours Imani caught up with Rob. Find the number of hours Rob traveled before Imani caught up.

Answer provided by our tutors

Let


x = number of hours Rob traveled before Imani caught up

v1 = 20 km/h the speed of Rob

v2 = 30 km/h the speed of Imani


After 2 hours Imani caught up with Rob that is


v1*(x+2) = the distance that Rob traveled (we are using the fromula distance = speed * time)

v2*2 = the distance that Imani traveled


these distances are equal thus


20*(x+2) = 30*2


x = 1 hours


Rob was traveled 1 hour before Imani started.


Let


x = number of hours Rob traveled before Imani caught up

v1 = 20 km/h the speed of Rob

v2 = 30 km/h the speed of Imani


After 2 hours Imani caught up with Rob that is


v1*(x+2) = the distance that Rob traveled (we are using the fromula distance = speed * time)

v2*2 = the distance that Imani traveled


these distances are equal thus


20*(x+2) = 30*2


x = 1 hours


Rob traveled 1 hour before Imani started.