To find the constant of proportionality for Jimmy, we need to divide the number of pages he reads by the number of minutes it takes him. So Jimmy's constant of proportionality is 15/5 = 3 pages per minute.
To find the constant of proportionality for Carlo, we need to divide the number of pages he reads by the number of minutes it takes him. So Carlo's constant of proportionality is 12/6 = 2 pages per minute.
To compare the proportional relationships, we can say that for every minute, Jimmy reads 3 pages and Carlo reads 2 pages. This means that Jimmy reads faster than Carlo.