XPath: select parent node when child propertyvalue starts with value

I need to select all parent nodes of type FOO where BAR nodes are childs and the BAR node has a attribute A that starts with X.

e.g. In the example below, i would like to select FOO (id = A) because i have a BAR with attribute A starting with an X.

<rumba>
  <latin>
    <FOO id="A">
      <BAR id="1" A="XYZ" />
      <BAR id="2" A="ABC" />
    </FOO>
  </latin>
  <salsa>
    <FOO id="B">
      <BAR id="3" A="UVW" />
    </FOO>
  </salsa>
</rumba>

I am pretty sure this can be done in XPATH, but I can't get my head wrapped around this one.