How To add the minimum support..

Question

Hi .. i am on last stage for my project. I want to ask that how to add the formula in my program to eliminate those not fulfill the condition.
for example:
Now, my item and support values is like this
item support
1: 13
3: 13
4: 13
2: 7
5: 1

after i add in my minimum support from Rich text box, is 3% .Those items that cannot fulfill 3% will be eliminate from the item and support values.
I tried many times already.
But its doesn't work for my program and my program can not run.
Hope someone can help me....thanks you.
here is the coding for my item and support value

 var v = from k in SingleI.Keys
                  orderby SingleI[k] descending
                  select k;


          SingleSupport.Clear();
          foreach (var k in v)
          {
               SingleItemValue.AppendText(k + ":" + SingleI[k] + "\r\n");
               
               hs1.Add(k);
          }