Rita is reading a five-chapter book with 95 pages. Each chapter has three pages more than the previous one. How many pages does the first chapter have? Think carefully first, then make a decision:
Let P be the number of pages in the first chapter. The second chapter has P + 3 pages. The third chapter has P + 3 + 3 = P + 6 pages. The fourth chapter has P + 6 + 3 = P + 9 pages. The fifth chapter has P + 9 + 3 = P + 12 pages. The whole book has P + 3 + P + 6 + P + 9 + P + 12 = 5P + 30 = 95 pages. Thus, without the 30 extra pages from additional chapters, 5P = 95 - 30 = 65 pages. Therefore, the first chapter had P = 65 / 5 = 13 pages. So, the answer is 13.