Iterating through file to find specific subsets of lines

[thegirlm0nkey]

Hi - getting extremely stuck and would love some insight! I have a file which contains sequential numbers (actually genomic co-ordinates, I'm an amateur bioinformatician!) and an associated score. I need to extract regions where the score dips below a certain level. The file looks something like this:

1  50
2  50
3  1
4  10
5  49
6  8
7  50
8  5
9  5
10  40

So in this example - the first number on each line is the co-ordinate, and the second is the score. I need all the regions scoring less than 50, so for the small example above, I would get something like:

3   6
8   10

Hope that makes sense - I'm basically looking for the first and last positions where the score is less than 50. So far I have slurped the file into an array like this:

foreach my $line (@lines) {
 chomp $line;
 my @columns = split(/\t/, $line);
 my $score = $columns[1];
   if ($score < 50) {
    #something here...    
   }
}

But I'm stuck with the 'something here' - I need to keep track of the first time a score of less than 50 is seen, and the last time it is seen before it goes above 50, and capture the two corresponding $columns[0] numbers. Really hope I've explained this properly! TIA.