OK, I'll add a lot of points! 1. There are 270 books on the two bookshelves. Now put 1 / 6 of the books on the first bookshelf into the second bookshelf. At this time, the ratio of books on the two bookshelves is 5:4. How many books are there on each bookshelf? 2. The area ratio of the front, upper and left sides of a cuboid is 7:3:2. It is known that the upper area is 50 square centimeters. What is the surface area of the cuboid?

OK, I'll add a lot of points! 1. There are 270 books on the two bookshelves. Now put 1 / 6 of the books on the first bookshelf into the second bookshelf. At this time, the ratio of books on the two bookshelves is 5:4. How many books are there on each bookshelf? 2. The area ratio of the front, upper and left sides of a cuboid is 7:3:2. It is known that the upper area is 50 square centimeters. What is the surface area of the cuboid?

1. Finally: a 270 * 5 (4 + 5) = 150, B 270 * 4 (4 + 5) = 120, Original: a 150 △ 1-1 / 6) = 180, B 270-180 = 90, 2, front: Top = 7:3, front area = 7 * 50 / 3 = 350 / 3 square centimeter, top: left = 3:2, left area = 50 * 2 / 3 = 100 / 3 square centimeter, cuboid surface area = 2