antmavel:
from my experience (doing poorly the first time and then doing better the second time) - take some time off for now. take a few weeks to relax, and then come back to the gmat with a vengeance!
regarding verbal - SC seems to be the hardest thing for non native speakers, so that bears most risk. but you can practice CR and RC and get really good at that. believe it or not, CR is almost a science... just break the statements down into pieces, find the argument, and you will come up with a solution. for RC - the answer is right infront of you (literally). all you need to do is get good and sifting through the clutter. doing well on CR and RC will nullify or mitigate any risk in SC (it helped me).
as far as quants go - i am sure you have what it takes to get to the high 40s. DON'T LET ANYTHING SCARE YOU! in the example you posted above, here's how i would solve it quickly:
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For instance : [square root (0.000025) * (5^3)]/ [0.5 * 10^5]
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1. first, see that there are a lot of 5s and 10s... and you're multiplying and dividing so there is a lot of cancelling out you can do... this is not as bad as it looks. break the problem down to basic parts, solve, and then put it back together..
sqrt(0.000025) = sqrt( 25/1000000 ). that looks really easy to solve doesn't it? it now becomes 5/1000. also, note that (.5 * 100000) = 100000/2 = 50,000.
so the equation can now be re written:
[(5^4)/1000]*[1/50000]
if you cancel out the fraction and reduce, you quickly can get rid of all the 5s and end up with 1/8000. note that 1/8 is 0.125, so 1/8000 has to be 0.000125.
there are lots of ways of doing problems like these, and this is only one solution, but you really don't need to be scared of these. just look at the question, "see" the concepts (reducing, quick multiplying, etc) and then attack. remember, this question CAN be solved in 2 minutes - you ask yourself what concepts the writer of the question was trying to test.
anyway, sorry for the long post. i wish you the best!
ecdysis.