using round

function floorWithPrecision($value, $precision = 1) {
    return round($value - ( 0.5 / ( 10 ** $precision ) ), $precision, PHP_ROUND_HALF_UP);
}

/*
As a function
*/

echo floorWithPrecision(49.955, 2);

/*
49.95
*/

echo PHP_EOL;

/*
Same but no function both are keeping float
*/

echo round(49.955-0.005, 2, PHP_ROUND_HALF_UP);

/*
49.95
*/