Ok, it's time to end this contest now. Looks like not many friends are interested in this tank? It's a pity that we can not give away this prize since less than half of required entries. But as usual, we have chosen a friend to reward with $20 gift card. Congrats to @pateralus9
For the vape quiz, if any of you have interest, here is the correct answer.
It's not a normal math, it's like a logical-mathematical reasoning. Just for fun.