I'm doing some of the exercises in Susanna Epp's Discrete Mathematics with Applications, Fourth Edition and there's one answer to the exercises that I don't understand. In Exercise 1.3, No. 9.c:
What fraction of the relations from { 0, 1 } to { 1 } are functions?
And the answer is 1/4 (one-over-four). Can anyone tell me how to get to that answer?
To be honest, I barely understand the question.