extjs4.2 - How to let two element occupy 30% and 70% in extJs -

i want let 2 textfield exists in same line , occupy 30% , 70% respectively.

{ columnwidth : 1.0, items : [ { anchor: '30%', fieldlabel : 'a', xtype : 'textfield', value : "" } ] }, { columnwidth : 0.9, items : [ { fieldlabel : 'b', xtype : 'textfield', anchor: '70%', value : "" } ] } 

ext.require('*');  ext.onready(function(){      new ext.panel.panel({         renderto: document.body,         width: 500,         height: 200,         layout: 'hbox',         defaulttype: 'textfield',         items: [{             flex: 3         }, {             flex: 7             }]     });  });