The amount of fuel consumed by the engines of a jetliner on a flight between two cities is a normally distributed random variable X with mean 5.7 tons and standard derivation 0.5 tons Carrying too much fuel is inefficient as it slows the plans If, however, too little fuel is loaded on the plane, an emergency landing may be necessary.

What should be the amount of fuel to load so that there is 0.99 probability that the plane will arrive at its destination without emergency landing.