getGross( 71, 3.4,  14, 6);
getGross( 48, 6.4,  29, 6);
getGross(100, 5.0,  10, 24);
getGross(100, 5.0,  19, 48);
getGross( 70, 7.5, 485, 24);
getGross( 67, 5.0, 574, 36);
getGross( 72, 6.5, 293, 24);
getGross( 85, 6.5,  41, 48);

function getGross(rating, avgPrice, nReview, devLength) {
    var soldPerReview = 17 + 36 * (rating - 48) / (71-48);
    var sold = nReview * soldPerReview;
    var gross = sold * avgPrice;
    var incPerMonth = gross / devLength;
    trace(soldPerReview, sold, gross, incPerMonth);
    return gross;
}