#!/usr/bin/env perl -l

use strict;
use warnings;

my %score;

{
    local $/ = "";

    while (<DATA>) {
        /\A(\w+).*?(\d+)\D*\z/ms;
        ++$score{$1}{count};
        $score{$1}{total} += $2;
    }
}

for (sort keys %score) {
    print $_, ' Average ', $score{$_}{total} / $score{$_}{count};
}

__DATA__
Jack
Student ID - 12445
Math Score - 45

Jill
Student ID - 234254
Math Score - 90

Jack
Student ID -12445
Math Score2 - 33

Jill 
Student ID - 234254
Math Score2 - 10