25-75: The app on the left takes up just 25% of the screen, with the right app taking up 75%.50-50: Each app takes up the exact same real estate on the iPad.
On certain iPads, you can also resize Split View panes for a 50-50, 25-75 or 75-25 split in a horizontal orientation when holding the tablet vertically, you'll only have the 25-75 or 75-25 options. Depending on the screen size of your iPad, those two apps may be displayed as Compact (iPhone UI) or Regular (iPad UI) next to each other. Split View lets you have two persistent apps sitting side by side on your iPad.
