2、4:5:9

3、 15:35: 14

4. The connection ratio of three groups is 8: 12: 15, one group is 140/(8+12+15) * 8 = 32, and the other group is15.

5, fertile land: cotton field: other = 2 1: 6: 1, so each serving is 6 1600 divided by (2 1+6+ 1) = 2200, fertile land 2200 * 2.

6. One group: two groups: three groups = 15: 12: 8, one group is 15 divided by (12+8- 15) = 3 people, so there is * *.

3 * (15+12+8) =105 people.

7. Science and technology: composition: math = 9: 10: 14, each copy is 69 divided by (14+9) = 3 people, so math is more than composition.

3 * (14-10) =12 people

8. The total number of Party A and Party B remains unchanged. Party A accounts for 7/ 12 of the total, and after giving Party B 650 copies, it accounts for 3/7 of the total, so the total number is: 650 divided by (7/12-3/7) = 4,200, so the original number of Party A is 4,200 * 7//kloc-.

9. The total number of pages remains unchanged. The total number of pages is 30 divided by (3/8- 1/6) = 144 pages.

10, the total amount is unchanged, and the total weight is 130 divided by (4/5-7/12) = 600g, instead of 600 * 4/5 = 480g.

1 1, the latter two categories account for 2/3 of the total, and the total number of categories 2 and 3: 8 divided by (13- 1 1) multiplied by (13+1) = 99.