Reuters: A massive new fleet of flex-fuel cars in Brazil has prevented state oil company Petrobras from charging more for gasoline despite record world oil prices, the company said Friday. Petrobras downstream director, Paulo Roberto Costa, said consumers in Latin America’s largest country would stop buying gasoline and switch to cheaper ethanol if the price of the fossil fuel was raised to match world levels after being frozen since late 2005. "It doesn’t make sense hiking …