It is not important whether or not the test is easy, because the idea is that anyone who does get in has the ability or gift to select answers correctly. By the way, you should hurry because the applications are closing.
http://www.education.vic.gov.au/aboutschool/enrolling/selectentry/tests.htm
This website has archive selective school tests.
If you're really serious about Macrobertson, you should try going to Edukingdom or James An College. These places have teachers who teach you to do questions quickly. They provide new practice tests each week and essay topics. I have done both Edukingdom and James An, and Edukingdom is better for mathematics, while James An is better for teaching English.
http://jamesancollege.com/
http://www.i-ekc.com/
For numerical reasoning and verbal reasoning, there are 60 questions to complete in 30 minutes. For reading comprehension and mathematics, there are 50 questions to complete in 30 minutes. You will do one analytical essay (15 minutes) and one creative essay (15 minutes).
Generally, yes, it does lower your chances of getting in if others in your school are sitting the exam. But put into consideration that up to 10% of your school can be accepted, so it does not significantly change the odds.
Tips:
-Make sure you have a well lit study area, buy some sticky notes to stick on piles of homework you need help with.
-Teachers at school get suspicious if you start bringing in random questions from other places, so write them onto a separate piece of paper. The teachers at school would help.
-Organise a study time after school. If you have a really noisy family, study at the library.
-Delete social networking accounts or gaming sites that make you procrastinate. Get Mozilla Firefox with Leechblock (an addon) that blocks these sites.
-Don't tell anybody at school about sitting the exam, or you might be setting yourself up for disappointment.