In a town 55% of the adults hold a bank account, and 36% of those account-holders use net banking. Net-banking users are what per cent of the adults who hold NO bank account?

Take 100 adults. Account-holders = 55, of whom 36% = 19.8 use net banking. Adults with no account = 100 - 55 = 45. The question asks for the users as a share of THAT group: 19.8/45 = 0.44 = 44%. 19.8% is the users as a share of all adults - the answer to a question that was not asked, and the trap here. 36% repeats the given rate, and 45% is the size of the no-account group itself.