Here's one approach...

Instead of using a regex within the m// operator, this uses a regex within a split function. Whatever approach you take, the regular expression involved needn't be terribly complex.

my %counter;
while ( <DATA> ) {
    my ( $name, $number ) = ( split /\s+/ )[0,2];
    $counter{$name} += $number;
}
print "$_: $counter{$_}\n" foreach keys %counter;
__DATA__
Jack  Monday  4
Eddie Tuesday 6
Jack  Friday  7
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