When a user posts a challenge, e.g.
Given two hourglasses, one lasting 4 minutes, and one lasting 7 minutes, how do you measure 9 minutes precisely?
What's the correct form of replying to the challenge ?
Obviously, if the correct answer is there, staring you in the face then it'll be pretty tricky to not read it, thus spoiling the challenge for yourself.
Wouldn't it be best to put the answers in spoilers tags:
In that way, even if a challenge has been answered correctly, there's still some challenge left for casual readers.