Emissions of nitrogen oxides, which are major constituents of smog, can be modeled using a normal distribution. Letxdenote the amount of this pollutant emitted (in parts per billion) by a randomly selected vehicle. Suppose the distribution ofxcan be described by a normal distribution with =1.5 and =0.4.

A city wants to offer some sort of incentive to get the worst polluters off the road. What emission levels constitute the worst 10% of the vehicles? (Round your answer to four decimal places.)The worst 10% of vehicles are those with emission levels ---Select--- greater than equal to less than a level of parts per billion.