The function that defines the cost of the rice based on the weight is C = P100*W.
The first step is to determine the cost per weight of rice. In order to do this, divide the total cost bought by the total pounds bought.
Cost per pound = P400 / 4 = P100
Cost based on the weight = P100*W
Where:
To learn more about division, please check: https://brainly.com/question/194007