Triple Science?

I'm not a fan of Triple Science but i'm considering to take it. I'm not sure how it works but I am pretty good at Science apart from Chemistry and my average grade is a B the lowest I get is a D there all from Chemistry. I am aware of the risks of taking this...I don't want to do a job science related I want to do something related to Geography. The system is different in my school you need to get higher than the set above you to enter Triple Science. Problem is...i'm not sure if I should take Triple Science. If I do well in the mock exams in the end of year 10 then i'll be put in for Triple but if I deliberately fail to get Double Award science there is a risk i'll end up doing Core :/

An easily solved problem: simply speak to the science department in your school (preferably the head of the science department) and express your concern about triple science, that you aspire to go into geography and that you're not planning on having a -direct- job within science.

Speaking of which, Geography is considered a science so you will be going into it. Physics, Chemistry and Bio are useful for Geography but I know many who have done double science and have gone on to do Geo AS/A2 and passed.

Ok, the reason why I don't want Triple Science is because i'm really bad at Chemistry. If I take Triple Science and get a disgraceful grade at Chemistry will it pull down my overall grade?
Lets say I get a D+ in Chemistry and 2 B's in Biology and Physics what would my average grade be?