I upgraded to Mavericks & have both old & new Pages icon in dock.

Hello there, pillfield.

The following Knowledge Base article explains the reasoning behind the older version of the iWork applications not being removed from your computer:

About the new iWork for Mac: Features and compatibility

http://support.apple.com/kb/HT6049

Since features were still to be rolled out:

In the meanwhile, you can continue to use these features by accessing the previous versions of the iWork applications which remain installed on your Mac. The previous versions can be found in Applications > iWork ’09.

If you are comfortable with the new applications and want to delete the older versions of the iWork applications, this article provides some information on how to do that:

OS X Mavericks: Install, update, and uninstall apps

http://support.apple.com/kb/PH14299

You may also want to review this article to remove the Alias of the application from your dock, once you delete the application:

Mac Basics: The Dock

http://support.apple.com/kb/ht2474

To remove an item from the Dock, drag its icon an inch or more off the Dock and wait a couple seconds, then release; the icon will disappear in a poof of smoke. There are some icons that you can't remove from the Dock, such as the Trash and the Finder.

Don't worry, you aren't permanently removing the item from your computer; you simply got rid of its Dock icon. If you want that item back in the Dock, locate the application, file, or folder in the Finder (or with Spotlight), and drag it back into the Dock.

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.

What is your question?

It's best to keep your prior version of Pages as the newer version has less features and functionality as the previous version. You will see in /Applications a folder called iWork '09. This has your prior versions of KeyNote, Pages and Numbers in case you need to open a file with those versions.

If you are simply wanting to remove one of the Pages icons from your Dock, you can left click and drag it to the middle of your screen and release to remove it.