That's probably what it used to be... +6 each day to see the clue...

But they lowered the amount it takes because, I suppose, people were whining (and I will use that term) that they couldn't earn the candies fast enough to keep up.

(I say - if they weren't buying 20 of each item every day, they'd be able to see the clue and then spend all of their candies at the end of the event... But I suppose some people wouldn't agree with me. Yay democracy. XD )