For the paper 1 factorising question did anyone else get a(a+b)+b(a+b)? And for the one about whether mean or median was more representative, which one did you say? I put mean but apparently that's wrong because the randomly huge number skewed it...
And for the emissions one, I think it was just one of those 'the price of the house falls by 3.5% each year' questions in disguise. The reason you can't do 15*4 to get 60% is because each time, after the 15% has been taken off, the emissions are lower, and therefore the 15% of it is lower... if that makes any sense. So 100-15% = 85, then 85-15%=72.25, not 100-(15+15)%=70.