As pointed out by iforget, these puzzles are clogging up the forum and answers come out way too quickly for some to catch up. So here's week one of the puzzle thread! I'll post one a week to get things going and see how things go from there.
There are 3 hints for each puzzle, so use teamwork to decide when one is needed.
LET'S GET OUR BRAINS WORKING AGAIN
Puzzle 1 - Brother and Sister
A boy and his big sister are sitting around the kitchen table chatting.
"You know, Sis, if I took away two years from my age and gave them to you, you'd be twice my age, huh!"
"Well, why don't you just give me one more on top of that? Then I'll be three times your age."
So just how old is each sibling?
When you read this, don't scroll down until you think you've got the answer, then post. That way it wont be spoiled for you!