a. X is better, for it has a net result value of 3, whereas Y has a net value of -1.
b. X is better, for it has a net result value of 15, whereas Y has a net value of 10. The fact that in Y no one is unhappy does not count in itself. It would count only if the unhappiness of the 5 in X would cause more unhappiness.
c. Y is better, for it produces 12 hours of pleasure, whereas X produces 10 hours.
d. X is better, for although it makes fewer people happy, it makes them very happy, and it also makes 1 more person unhappy than Y but they are only mildly unhappy. If you use a scale such as in the text, it would be the same. X is better for it produces 5 x 10 degrees (50) and 3 x -2 (-6) or = 44 person/degrees. Y produces 6 x 5 degrees (30) and 2 x -10 (-20) = 10 people/degrees.