Hello Wilbur,
Let's call x the weight of one magazine
4 magazines weigh 8/3 pounds ----> 4*x = 8/3
To solve for x, divide both sides by 4 ----> x = 8/12 = 2/3 lb
Each magazine weighs 2/3 of a pound. Therefore, the unit rate is 2/3 pounds per magazine.
Cheers.