Rounding Mechanism to nearest 0.05

Question

I would like to solve rounding mechanism by using php4,5.2 and below (not 5.3) Currently I am doing 0.05 rounding, something like this page:

http://www.bnm.gov.my/in

Answer 1

function round5Sen ($value) { 

    return number_format(round($value*20,0)/20,2,'.','');
} 

echo round5Sen(155.13);
echo "\n";
echo round5Sen(155.12);
echo "\n";
echo round5Sen(155.0);
echo "\n";
echo round5Sen(155.18);
echo "\n";