PHP Round up to specific number | Round to nearest number | Round to next multiple of number

<?php
#Round to the next multiple of 5, exclude the current number
function roundNumberToUp($n, $x = 5)
{
    return round(($n + $x / 2) / $x) * $x;
}
roundNumberToUp(10);    #10
roundNumberToUp(10.2);  #15
roundNumberToUp(11.5);  #15

#Round to the nearest multiple of 5, include the current number
function roundNumberToNearest($n, $x = 5)
{
    return (round($n) % $x === 0) ? round($n) : round(($n + $x / 2) / $x) * $x;
}
roundNumberToNearest(10);   #10
roundNumberToNearest(10.3); #10
roundNumberToNearest(10.5); #15
roundNumberToNearest(11.7); #15

#Round up to an integer, then to the nearest multiple of 5
function roundNumberToNearestAsInteger($n, $x = 5)
{
    return (ceil($n) % $x === 0) ? ceil($n) : round(($n + $x / 2) / $x) * $x;
}
roundNumberToNearestAsInteger(10.3);    #15
roundNumberToNearestAsInteger(11.7);    #15