The three gardeners (as playing cards) painting the roses red. An illustration by JVL
in Lewis Carroll's Alice's Adventures in Wonderland, Artists' Choice Editions, 2009.
The sum of the three cards (7+5+2) =14.
14 x 3 (the three gardeners) equals that magic number of 42.
Here is the beginning of the text by Lewis Carroll:
CHAPTER VIII The Queen's Croquet-Ground
A large rose-tree stood near the entrance of the garden: the
roses growing on it were white, but there were three gardeners at
it, busily painting them red. Alice thought this a very curious
thing, and she went nearer to watch them, and just as she came up
to them she heard one of them say, `Look out now, Five! Don't go
splashing paint over me like that!