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

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

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

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

echo $totalScoreWeighted;