Hi,
Two days before I update my phone to N.
Today I saw a icon in my files labeled "Installation Files". When I opened it there were 247 apk files and total size of them was 4.7GB.
So I took a backup of them in pendrive and delete all apk files from my files.
After deleting apks I test that are all apps working properly. Yes all is well. Then i Restart my phone. It is working properly.
So deleting apks from my files i get 4.7gb free space. Thanks Samsung.