Align Adsense Widget on Blogger

I want to align my adsense widgets on blogger so that they are side by side.

like this: (Adsense 1)(Adsense 2)

NOT: (Adsense 1)
(Adsense 2)

My code as of the moment is:

<div id='main-wrapper'>
        <b:section class='main' id='main' showaddelement='no'>
<b:widget id='AdSense1' locked='false' title='' type='AdSense'/>
<b:widget id='AdSense3' locked='false' title='' type='AdSense'/>
<b:widget id='Blog1' locked='true' title='Blog Posts' type='Blog'/>
<b:widget id='BlogArchive2' locked='false' title='Blog Archive' type='BlogArchive'/>
</b:section>

Code (markup):

How do I align 'Adsense 1' to be left and 'Adsense 3' to be right, but make them stay side-by-side

I want it to look like this basically: