Question 950471
Okay in order for us to solve this problem we need to know a fundamental physic's equation:

{{{s=(d/t)}}}  

This is equation:(*1)

Where:
s=speed
d=distance
t=time

With this equation and using simple algebraic manipulation we can find the distance that Carolyn has traveled; using her speed and the amount of time that has passed. 

{{{d=s*t}}}

Knowing how fast Alicia is traveling and how far Carolyn has traveled we can again use simple algebraic manipulation of equation (*1) to find the time Alicia catches Carolyn.

{{{t=d/s}}}

Fun Fact: Equation (*1) is a fundamental idea in calculus and Newtonian physics. Velocity (speed with direction) is defined as:

{{{V=(ds)/(dt)}}}

This is known as a differential equation.
Where ds is defined as the change in position [or displacement]
And dt is defined as the amount of time that passes.

Hence you are doing calculus right now! :p