Facebook Interview Question Formatting a collection of times for a movie show time output using Linq is preferred

Question

class TimeObject
{
    DateTime time;
    bool isMatinee;
}

Given: {8:00, 9:30, 11:00, 12:10, 2:00, 4:00, 5:20} -- a collection of TimeObjects

Output: (8:00AM, 9:30, 11:00, 12:10PM, 2:00), 4:00, 5:20 -- return a string, oh and AM/PM should be picked up from localization strings

Caveats: AM/PM only shown for first time, ( ) encloses those elements whose matinee bool was set to true.

The problem is that I don't know how to print the above string.

Although I said that I was familiar with C#, the interviewer insisted on knowing how to accomplish this with the fewest lines of understandable code possible, ideally using LINQ. I could write it to the console, he explained, but I would have to remember to localise the AM and PM.

I definitely messed up by creating a slew of interim collections and other nonsense. It's simply a few lines of LINQ, he claims. I tried a few other things, but he kept directing me back to LINQ.