"en vaut la peine?"

Question

Why is it "le résultat en vaut la peine! " Where is the "de" it is replacing?

Accepted Answer

Hi Brittany,
The expression -
quelque chose en vaut  la peine = something is worth the effort (it)
So it is an idiomatic 'en' here.
It reminded me of the lovely expression-
Le jeu n'en vaut pas la chandelle 
Literally referring to when games of cards or dice were played by candlelight and you had to decide if the cost of the candle (an expensive commodity at the time) was worth playing the game.
It is now used figuratively to mean -
Don't waste your time it's not worth it!
Hope this helps!

Answer

It's -- once more -- a case of an idiomatic en. There are lots of those. And probably just as many uses for the idiomatic y.

Actually, this might be a nice lesson: a list of the 10 most commonly used idiomatic expressions using en and y. Would come in handy and make you sound more French.