You'll want to start by finding the equations of both lines. You are given two points for Juliet explicitly, and it is implied that wherever Juliet has her x-intercept is also on Mercutio's line. You can use this point as the second point for Mercutio. After doing so, you'll want to calculate the distance and rate of speed of Juliet. Use this to find out how long it takes her to reach the x-axis. Add 2 to this number to find Mercutio's rate of speed. After that, determine how long it takes for him to reach the y-axis.
The numbers part is up to you.