THE GROSVENOR HOTEL ( = 215 783095638 13254 ) is hosting a major musical event and all its rooms are full.Each guest has an appropriately digitally-coded pass-key ... apart from in ONE group, where one or more key/s are somehow confused or garbled. In which group, or pair, is the wrong key?

The process of decoding words is much the same. Be sure to read each question carefully - a misread number can mean the difference between CORRECT and CONNECT! Also, pay attention to the helpful comments after each question. They will shed much-needed light onto how the codes are worked out.