value into category !

Hi,

Can somebody help me with this. Based on ones download speed a value is created. Now i have 5 different category's.

1 = >(bigger then) 16
2 = between 12-16
3 = between 7-12
4 = between 5-7
5 = <(less then) 5

For example the value that is given is 11.5 how do i give the value an category number?

$speed = "11.5"

Here it is put in to category's

when it comes out it should be like

$cat = "3"

Hope somebody can help me with this.. cause i dunno where to start even 🙁

<?
If ($speed<=5) {
$cat=5;
} elseif (($speed>5) and ($speed<=7)) {
$cat=4;
}elseif ((($speed>7) and ($speed<=12){
$cat=3;
etc....
}

Thanks,

Must be sleepy :-)