The relationship being proportional means there is a value of k such that
... y = k·x
We are given the point (6 (pounds), 3 (dollars)), so we can write ...
... 3 dollars = k·6 pounds
Dividing by 6 pounds, we get
... (3/6) dollars/pound = k = $0.50/lb
Now, we can use x=1 pound to find the price (y),
... y = ($0.50/lb)·(1 lb)
... y = $0.50 . . . . the price of 1 pound of tomatoes.
