The path needs to be
Android/obb/com.example.android/
Its given here
Just store the file in
/mnt/sdcard/Android/obb/
EDIT
This is a screenshot of an emulator running API Level 17
EDIT 2
In case you don't have an Android folder inside the sdcard, just create one
This folder hierarchy needs to exist
/mnt/sdcard/Android/obb/
NOTE: This will work only on devices/emulators having an sdcard. In case of a device without external storage, the path is different (since an emulated sdcard is maintained). Check here