Renee left the restaurant traveling 20 mph. Then, 2 hours later, Karen left traveling the same direction at 28 mph. How long until Karen catches up with Renee?

Question

its a distance 

Answer 1

Hi,

distance=speed(time)

 

Let, t be the time it took for Karen to catch up with Renee;

Karen: d= 28t

Renee: d= 20(2 +t). Renee has already travelled for two hours.

 

The distance they travelled will be equal, when Karen catches up with Renee, so set the equations equal to each othe,

 

28t = 20(2 + t)

28t = 40 + 20t

 8t = 40

  t = 5

The answer is after 5 hours.