2 people decided to meet each other on a certain day between 5 and 6 pm. They arrive (independently) at a uniform time between 5 and 6 and wait for 15 minutes. What is the probability that they meet each other?
If X & Y are the times that each of the two friends arrive, then you want the probability that $\displaystyle
\left| {X - Y} \right| < 15$. Look at the graph. What is the probability that the random point (X,Y) is between the two blue lines?
Now, I have a word of caution for you. You have had a great many of these problems, probably take-home problems, worked for you. If you are doing any of this online you need to read my posting about online courses.
http://www.mathhelpforum.com/math-he...g-history.html