Four friends, A, B, C, and D, have different pets: a dog, a cat, a bird, and a fish. A does not have a dog. B has a bird. C does not have a cat. What pet does D have?
In a mixed number coding system, if the code for 'CAT' is represented by the numbers 3, 1, and 20, and the code for 'DOG' is represented by 4, 15, and 7, what is the code for 'GOD'?