var checkboxes = $('input[type=checkbox]:checked');
for (var i=0; i < checkboxes.length; i++){
var x = checkboxes[i].value;
var result = result*x + result;
}
var checkboxes = $('input[type=checkbox]:checked');
var percents=0;
var start_result=result;
var checkboxes_counter=1;
for (var i=0; i < checkboxes.length; i++){
var x = checkboxes[i].value;
var current_percent = start_result*x;
if(checkboxes_counter>1)
current_percent=current_percent+start_result;
result=result+current_percent;
checkboxes_counter++;
}