Clever!

Ohhhh, you are right, thanks a lot for your suggestion!

Thanks for downvoting the comment of the guy who tells you how to do correctly the things... Really rewarding...

I flagged it, yes. But that dosen't need editing your message (that would be a shame if anyone was able to edit others message. Flagging others message just require honor above a value). And that has nothing to do with the fact that you cannot anymore edit your message: messages are locked as soon as there are answers to them.

did you already edit it? I cannot see how to edit mine, and I see a spoiler flag now.

Spoiler flag please!

you can remove return string; because last line is automatically returned in ruby. and furthmore remove string assignment, because it's no longer used.

def reverse(string)
  string.split.reverse.join(" ");
end

you can get of else '' and change when 1..3 then ROMAN[i]*digit to when 0..3 then ROMAN[i]*digit

You can remove

elsif s == 5
  vals[t][1]

because

vals[t][1] + vals[t][0] * (s - 5) # returns vals[t][1] + 0

The to_f there was to cover the case where time is nil -- the litres method will always return a number.

[*1..num] does same thing as (1..num).to_a

Because 0.5 is a float already, you you don't need to convert time to a float (time * 0.5).floor is enough