I don't have enough space left in /var/cache/apt/archives, thus not able to install "gparted" so that I can increase Actual Size of Ubuntu vdi file. I have already increased the Virtual Size to 100 gig. But to make the Actual size to get increased as per Virtual size I need to perform partition on Ubuntu. Below are the details which can be helpful for you. Also let me know if there is any other way to perform the partition so that Actual size can be increased.
OS Inside my VM: Ubuntu 16.04 LTS VM Box: Version 5.2.8 r121009 (Qt5.6.2) Host: Windows 10