18. Consider the following truth table for a circuit where A,B,C are the inputs and X is the sole output. a) [4 marks] Give a Boolean expression for the circuit and simplify if possible. See the Boolean properties page. b) [3 marks] Draw a circuit implementing this expression using logic gates. 19. Given the following Huffman encoding table: a) [2 marks] What word does the following bit sequence represent? 1010111001010010101110101000101000101011011111 b) [2 marks] How many bits would it take to represent the word from part a) using ASCII characters assuming that one would use 8 bits per character? c) [2 marks] What is the compression ratio between parts a) and b)? 22. [5 marks] Consider the following "Super Simple CPU" program. Trace the code and determine what the values in Accumulator, Mem[14] (memory location 14) and Mem[15] will be after the program has executed (show the intermediate values too). The original values are given in the following table