Unable to locate package gcc-11

As an AI language model, I do not have access to your specific system and its configuration. However, the error message "Unable to locate package gcc-11" usually indicates that the package "gcc-11" is not available in your system's default package repository or that the repository is not properly configured. You may try the following steps to resolve the issue:

1. Update the package information on your system:
sudo apt-get update

2. Install gcc-11 from the repository:
sudo apt-get install gcc-11

3. If the package is still not found, check if you have added the correct repository for the package.

4. If the repository is not configured, you can add it manually.

It is also possible that the package may not be available for your specific operating system or version. In this case, you may need to search for alternative solutions or try installing an older version of gcc.