Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Walter Dix
Table title:
Major competition record
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Competition </th><th colspan=1 rowspan=1 > Venue </th><th colspan=1 rowspan=1 > Position </th><th colspan=1 rowspan=1 > Event </th><th colspan=1 rowspan=1 > Notes </th></tr>
<tr> <td colspan=1 rowspan=2 > 2008 </td><td colspan=1 rowspan=2 > Olympic Games </td><td colspan=1 rowspan=2 > Beijing, China </td><td colspan=1 rowspan=1 > 3rd </td><td colspan=1 rowspan=1 > 100 m </td><td colspan=1 rowspan=1 > 9.91 </td></tr>
<tr> <td colspan=1 rowspan=1 > 3rd </td><td colspan=1 rowspan=1 > 200 m </td><td colspan=1 rowspan=1 > 19.96 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=2 > 2011 </td><td class="highlighted"  colspan=1 rowspan=2 > World Championships </td><td colspan=1 rowspan=2 > Daegu, South Korea </td><td class="highlighted"  colspan=1 rowspan=1 > 2nd </td><td class="highlighted"  colspan=1 rowspan=1 > 100 m </td><td colspan=1 rowspan=1 > 10.08 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2nd </td><td class="highlighted"  colspan=1 rowspan=1 > 200 m </td><td colspan=1 rowspan=1 > 19.70 </td></tr>
</table>
Question:
Who won silver medals in both the 100 and 200 m at the 2011 World Championships?
Answer:
Walter Dix won silver medals in both the 100 and 200 m at the 2011 World Championships.