2. Analysis: Because it is an adjacent even number, the smaller number +2= the larger number; Also, because minor number +20%* major number = major number, there are: major number -2+20% major number = major number, so 20%* major number =2, major number = 10, minor number = 8;
3. Analysis: According to the condition of 1, distance A = 1.25 * distance B; According to condition 2, time A = 10/9 time b, so speed A = distance A/ time A =( 1.25* distance B) /( 10/9 time B) =9/8 (distance B/ time B) =9.
4. Analysis: A = B+30；; A-20 % A =(B- 18)/50%； It can be calculated that A originally stored 80 tons of grain;
5. Analysis: Because the volume of a cylinder with the same base and height is three times that of a cone, it is equivalent to integrating the cuboid population into four equal parts and finding the sum of three equal parts. Cuboid volume = 120, then the volume of cylinder is 90.
6. Analysis: Because the total amount of water is always the same, we can start from the idea that the total volume before pouring water = the total volume after pouring water. Total volume before pouring = 3 * 3 * 8 * pi+4 * 4 * 3 pi =120 pi; After pouring water, the water levels of A and B are the same, referred to as A high, 3*3* A high * Pi+4 * A high * Pi =25* A high * PI; Therefore, 120* pi =25* nail height * pi, which means the nail depth is 4.8cm；;
7. Analysis: It is not difficult to see that 3/4 of the whole journey is 50 meters less than 80% of the whole journey, and it is easy to calculate that the whole journey is 1000 meters. Moreover, when A walked 3/4 of the whole journey, that is, 750m, and B walked 80% of the whole journey, then their speed ratio was A speed: B speed = 15: 60. Then in this time, the distance traveled by A is a speed *( 1000/ B speed) = A speed/B speed *1000 =15/16 *1000 = 937.5 meters.