what airport express route goes to cosmopolitan hotel hong kong? what is cost per person?

You can take the airport express train from HK airport to Hong Kong Station, then catch a taxi to the hotel. It costs HKD90/person for the airport express. The taxi fare may be within HKD20.
You can also take bus E11 from the airport to Admiralty Station, Queensway, then transfer to bus 1 to Heard Street, Wan Chai Road and walk about several minutes to the hotel. It costs about HKD25/person.