A random sample of 25 seventh graders found that 10 enjoy practicing in a local contest making duct-tape wallets. Part a: If there are 480 seventh graders, give a proportion to estimate the number of seventh graders, n, who participate in the contest. Part b: Solve the proportion to estimate the number of seventh graders who participate in the contest. Part c: Solve a proportion to estimate the number of seventh graders, n, who do not participate in the contest. Three parts to this question