use strict;
use warnings;

my $aa = 2192;
my @volunteers = (('Ben') x 5, ('Scott') x 4, 'Jim');
for (0..98){
    my $bb = $aa + 200; 
    my $name = $volunteers[ $_ % @volunteers ];
    print "$aa-$bb\t\t$name", "\n";
    $aa+=201;
}
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As a side note -- $a and $b are special variables, don't assign these names to your variables.