$mReview = 100;
$mRating = 50;
$gRating = 60;

$totalScore = $mRating + $mReview + $gRating;

$mReviewWeighted = (($mReview / ($totalScore * 1.0)) * $mReview);
$mRatingWeighted = (($mRating / ($totalScore * 0.5)) * $mRating);
$gRatingWeighted = (($gRating / ($totalScore * 0.5)) * $gRating);

$totalScoreWeighted = $mRatingWeighted + $mReviewWeighted + $gRatingWeighted;

echo $totalScoreWeighted;