To find the constant of proportionality, we can divide the number of pages by the number of minutes for each person.
For Jimmy, the constant of proportionality is:
15 pages / 5 minutes = 3 pages per minute.
For Carlo, the constant of proportionality is:
12 pages / 6 minutes = 2 pages per minute.
To compare the proportional relationships, we can say that Jimmy reads at a faster rate than Carlo. For every minute, Jimmy reads 3 pages while Carlo reads 2 pages.