A telemetry unit on a weather balloon monitors 225 distinct meteorological warning conditions. In addition, the system's status register must reserve one unique binary state for 'Idle' and another unique binary state for 'Calibration'. What is the minimum number of bits required in the status register to represent all possible system states, and how many unused states will remain?
888 bits, 313131 unused states
888 bits, 292929 unused states
777 bits, 292929 unused states
999 bits, 285285285 unused states
117 exam-style questions on Edexcel GCSE Computer Science Binary, covering Binary representation and number of states, Unsigned and two's complement integers, Converting denary and 8-bit binary, Binary addition and binary shifts, Concept of overflow, and Hexadecimal notation and conversion. Each one has a worked solution and a mark scheme showing where the marks go.