The weight, w, of a plank varies directly with its length, (l). a 7.5 foot plank weighs 30 pounds. write an equation relating w and (l).
a. 225
b. 75
c. 3
d. 4(l)
explain i really don't understand and i have a test on the subject this week,

The table below represents the displacement of a fish from its reef as a function of time: time (hours) x displacement from reef (feet) y 0 4 1 64 2 124 3 184 4 244 part a: what is the y-intercept of the function, and what does this tell you about the fish? (4 points) part b: calculate the average rate of change of the function represented by the table between x = 1 to x = 3 hours, and tell what the average rate represents. (4 points) part c: what would be the domain of the function if the fish continued to swim at this rate until it traveled 724 feet from the reef? (2 points)