By almost 5% actually! https://www.google.com/search?q=11hr+22min+%2F+11hr+55min&oq...
$ units '1-(11hr+22min)/(11hr+55min)'
Definition: 0.046153846However I just discovered that if you hit command spacebar and paste that into the spotlight search it gives the right answer! Spotlight has always done simple unit conversions but it didn't used to be able to do calculations with units in them. I wonder when that was introduced...
GNU Units is far more featureful (and useful IMO).
You can install that, as "gunits", using Homebrew.
The command to use it is `gunits` though.
It's trivial to find the actual package name using 'brew list | grep units'.
See note 2: <https://news.ycombinator.com/item?id=31449413>