For 5th grade which equation provides the best estimate of the product of 1.7 and 3.2

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min

Find solution of the linear equation y = 2/3x + 1/3

Math i have no idea how to do a and b