6 Questions I ripped off the 2008 Mathematics Challenges - Apirl Edition (for 15+)

Hello everyone, since everyone here all like Maths alot (well I do). Let's try some challenging challenges... I ripped 6 problems from a booklet called 2008 Mathematic Challenges - Apirl Edition (for 15+) from my local newsagent. And I find them quiet challenging so if you're intrested or in for a challenge. Try afew, and post your full working out and answers, so we can discuss about it. Enjoy!

*MUST ANSWER IN FULL OR ELSE IT'LL MEAN YOU CHEATED*