(Score for Question 1: ___ of 6 points)
1. Explain whether each following example is proportional or non-proportional.
(a)
(b)

(c) A gallon of milk costs $1.99. A half-gallon of milk costs $3.89.
(d)
x y
2 13
3 19.5
4 26
5 32.5
Answer: