#! perl -slw
use strict;

# do open and lock stuff
my @students = map{ [ split ] } <DATA>;

print "Student scores\n------------";
print "@$_" for @students;

my %grades;
for my $grade ( 0 .. 2 ) {
	$grades{ $grade } 
		= $students[ 0 ][ $grade ] * 0.2
		+ $students[ 1 ][ $grade ] * 0.25
		+ $students[ 2 ][ $grade ] * 0.25
		+ $students[ 3 ][ $grade ] * 0.3
}
print "\nGrades\n--------";
print "$_ => $grades{ $_ }" for sort keys %grades;


=Output
P:\test>337154
Student scores
------------
1 2 3
2 1 3
3 1 2
3 2 1

Grades
--------
0 => 2.35
1 => 1.5
2 => 2.15
=cut

__DATA__
1 2 3
2 1 3 
3 1 2
3 2 1