<image>School A and School B have inventories of 12 computers and 6 computers respectively. They decided to support School C with 10 computers and School D with 8 computers. It is known that the transportation cost for sending one computer from School A to School C and School D is 40 yuan and 10 yuan respectively; the transportation cost for sending one computer from School B to School C and School D is 30 yuan and 20 yuan respectively.

(1) Let the number of computers transported from School A to School C be x units. According to the image below, find the function W (yuan), which represents the total transportation cost in terms of x;
(2) Find the transportation plan that minimizes the total transportation cost and determine the minimum cost.