+845 
for this one i did:
convert 45kmh^-1 to ms^-1 which is 12.5ms^-1
my driving force F = -10000 -25000x
change in kinetic energy= 0- (0.5*30000*12.5^2) = -2343750J
\(\int_{0}^{x} -10000 -2500x\)
which gave me expression -10000x - (2500x^2)/2
then -10000x - (2500x^2)/2 = -2343750J
solve by quadratic:
-10000x - (2500x^2)/2 + 2343750 = 0
which is x=39.48 x=-47.48
My answer should be 78.7M according to the markscheme
please help thanks
