Ruby code to parse and analyze social media stats in json format
Good work.

Here are some points where you can improve:


You can use input.sum { |x| x["like_count"] }.to_f instead of input.map { |x| x["like_count"] }.inject{ |sum, el| sum + el }
It is a good idea to do calculations with BigDecimal instead of Float.
435 is a magic number, you can put it into a constant with a good name.
The spaces before the parentheses aren't usual in the Ruby community style guide.
Check the dig method available for Hash instances.
You can use the new syntax for Hash instances when the keys are symbols: { hello: "world" }
Use double-quotes or single-quotes, you're mixing both.