Google is now bolding the answers in the search results when quick answers are displayed at the top of the page, in the knowledge graph box area.
For example, a search for [airline pilot salary] shows $98,410 bolded, even though the query doesn't mention that number:
Or a search for [the average age of a college student] bolds 25:
This was spotted by Wissam Dandan and posted on Google+.
From there, Uwe Tippmann from ABAKUS showed that if you search for the same airline salary in Google UK you get different smart numbers and even ranges of salaries bolded.
Google has long bolded your search query and even synonymous of your query but the answers, that seems new.
I should add that it is also bolding the answer in the normal search results, not just the answer box.
Forum discussion at Google+.
