<apex:page standardController="Account" recordSetVar="accounts">
    <apex:form >



<apex:pageBlock title="Account List" id="account_list">


<table>
  <apex:repeat value="{!accounts }" var="acc">
    <tr>
      <td>
       <apex:selectRadio layout="pageDirection">
      <apex:selectOptions value="{!acc.Name}"/>
      </apex:selectRadio >
      </td>
    </tr>
  </apex:repeat>
</table>


<h1> Contacts</h1>

<table>
  <apex:repeat value="{!accounts }" var="acc">
    <tr>
      <apex:repeat value="{!acc.Contacts}" var="cont">
      <td><apex:outputText value="{!cont.Name}"/></td>
      </apex:repeat>
    </tr>
  </apex:repeat>
</table>


</apex:pageBlock>

    </apex:form>
</apex:page>