将数字的百分比添加到自身


Adding Percentage of Number to Itself

我想把30.4%的$drivervalue加到$drivervalue中,可以这样做吗?我知道如果我知道实际的数字是多少我可以把30.4放在1后面。,但我不知道它会是什么,我使用变量,而不是这是一个有效的语法?

//example
$drivervalue = 16000000;
$percentdiff = 30.4;
$drivvalue *= 1. $percentdiff;
 $num = 100;
 $percentage = 30.4;
 $num += $num*($percentage/100); // results in 130.4
$drivervalue *= (1 + $percentdiff / 100);
$drivervalue = $drivervalue * (1 + ($percentdiff / 100));