my $answer=[q;7566626f206f7420756f7920656d6f636c65772049;];
print join''=>reverse split''=>pack H42=>$answer->[-1]=>eval;

tachyon

Here is a quick dissection, you definitely got slack at the end!

$a="0"x((eval join'+',1..10)-5);    # $a = '0'x50 
($a)=map{$_}$a=~y/0//;              # $a = 50;
$b=pack("C",67);                    # $b = 'C'
$_=pack($b,pack($b,$a+4).pack($b,$a+6)); # $b = 'D'
eval;                               # eval $_ => calls D()
# preceeding code could be replaced by &D so it is basically fill;
sub D{
    $_=eval(join'*',1..5)-eval(join'+',1..9)-1;         # 74  => J  
    $_.=$".ord(chr($_+ord'+'));                         # 117 => u
    $_.=$".ord(chr($_+(eval(join('+',2<<4,2<<2,2)))-1));# 115 => s
    $_.=$".ord(chr($_+(eval(join('+',2<<4,2<<2,2)))));  # 116 => t   
    print map{chr}split;                            # Just
    print map{chr}32,65,110,111,116,104,101,114;    # Another         
+   
    print map{chr}32,80,101,114,108;                # Perl
    print map{chr}32,72,97,99,107,101,114;          # Hacker
}

# note eval join '+'(x..y) sums the joined numbers
# eval join '*' (x..y) multiplies the joined numbers
# $" is output record spearator default ' '
# Binary '<<' returns the value of its left argument shifted left 
# by the number of bits specified by the right argument.
# thus dec 2 (b10) << dec 4 = b100000 = dec 32
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