7. Research on how students solve word problems contained the following incident. Dana, a seventh-grader in a gifted program in mathematics, was asked to solve the following problem: A carpenter has a board 200 inches long and 12 inches wide. He makes 4 identical shelves and still has a piece of board 36 inches long left over. How long is each shelf? Dana tried to solve the problem as follows: She added 36 and 4, then scratched it out, and wrote 200 X 12, but she thought that was too large so she scratched it out. Then she tried 2400 - 36, which was also too large and discarded it. Then she calculated 4 X 36 and subtracted that from 200, getting 56. She then subtracted 12, and got 44. Dana used a weak strategy called "Try all operations and choose." She obviously did not know what to do with this problem, although she was very good at solving one-step problems. Do a quantitative analysis of this problem situation, and use it to make sense of the problem in a way that Dana did not. Use your analysis to solve the problem.8. The problems listed below, and in Exercise 9, are from a Russian Grade 3 textbook." Solve the problems and compare their conditions and solutions. a. Two pedestrians simultaneously left two villages and walked toward each other, meeting after 3 hours. The first pedestrian walked 4 km in an hour, and the second walked 6 km in an hour. Find the distance between their villages. Meet ? 4 km per h 6 km per h b. Two pedestrians simultaneously left two villages 27 km apart and walked toward each other. The first one walked 4 km per hour, and the second walked 6 km per hour. After how many hours did the pedestrians meet? (Meet 27 km 4 km per h 6 km per h c. Two pedestrians simultaneously left two villages 27 km apart and walked toward each other, meeting after 3 hours. The first pedestrian walked at a speed of 4 km per hour. At what speed did the second pedestrian walk? Meet 27 km 4 km per h