dont just think go to
http://community.boredofstudies.org/688/mathematics-extension-2/126181/solution-maths-ext-2-a.html
it has solution and i got about 72 -73 raw i hope they scale to 80%
i didnt do it but i when to my teacher and he said u remember the property of the ellispies and i got NO and then he goes PS + PM = 2a so the major is 5 and i got dam i guessed 6 :(