_____________This is the Class where i am facing problem------------------------------
public class SaveMultiObj {


    public humanresource__c hr{get;set;}
      public CandidateHr__c cand{get;set;}
      public AdminService__c admin{get;set;}
        
        public SaveMultiObj(){
        hr=new humanresource__c();
        cand=new CandidateHr__c();
        admin=new AdminService__c ();
        }
    public void custsave(){
     
      insert hr;
     cand.HumanResource__c=hr.id;
     cand.rank__c=hr.rank__c;
     cand.last_name__c=hr.last_name__c;
      insert cand;   
     }
    public void custUpdate() {
      CandidateHr__c cand1 =[select id,last_name__c,rank__c,name from candidatehr__c where name=:cand.name];
       cand1.last_name__c=hr.last_name__c;
       cand1.rank__c=hr.rank__c;
       update cand1;
      
     admin.CandidateHr__c=cand1.id;
     admin.rank__c=cand1.rank__c;
     admin.last_name__c=cand1.last_name__c;
      insert admin;         
    }   
   }
-------------------------This is Test Class which is related to above Class ---which able to cover only 68%--------
@isTest
public class SaveMultiObj_TC
{
    static testMethod void testMthd()
    {
        SaveMultiObj s=new SaveMultiObj ();
        s.custsave();
        s.custUpdate();
        s.hr=new humanresource__c (name='xxx');
        s.cand=new CandidateHr__c (name='yyy');  
        insert s.cand;
        s.cand.name='yyo';   
        update s.cand;
        s.admin=new AdminService__c (name='uuu');
        insert s.admin;
    }
}