Best-Selling Novel The number of copies of a best-selling novel sold t weeks after it was introduced is given by N(t) = (5+ 4t)5/3 (1t 30) where N(t) is measured in thousands. (a) How many copies of the novel were sold after 24 weeks? (Round your answer to the nearest integer.) copies (b) How fast were the sales of the novel changing after 24 weeks? (Round your answer to the nearest integer.) copies/wk