Getting the slope of all the tables (by getting the difference between succeeding y values and x values and getting the ratio of the difference in y and difference in x), I was able to determine that the third table (31, 18) and the fifth table (12, 7) have lower unit rate than the rate represented in the equation y=3/5x (which has a slope of 0.6). To prove this:
third table calculation:
m (slope) = (y2-y1)/(x2-x1) = (36-18)/(62-31) = 0.58 (less than 0.6)
fifth table calculation:
m (slope) = (y2-y1)/(x2-x1) = (14-7)/(24-12) = 0.58 (less than 0.6)