That is, (8× 6× 4) ÷ (2× 2× 2) = 24.
Second, the solution: the reduced surface area is equal to twice the original bottom area of each cylinder, and the length of the new cylinder is twice the original length of each cylinder. Therefore, the original bottom area of each cylinder is 25. 12 ÷ 2 = 12.56 square centimeters, the original length of each cylinder is 12 ÷ 2 = 6 centimeters, and the original volume of each cylinder is 12.56× 6 = 75.36 cubic meters.
Solution: The target water depth is 1.5m, so the volume of the target water is 50× 30× 1.5 = 2250m3, so the time is 2250 ÷ 200 =11.25m. ..
Solution: The water pump pumps 0.2× 0.2× π× 0.6 = 0.024π cubic meter per second, so its pumping capacity per minute is 0.024π× 60 = 1.44π cubic meter.
5. Solution: On the drawing, the long right-angle side is 5.4 ÷ (5+4) × 5 = 3cm, and the short right-angle side is 5.4-3 = 2.4cm .. So the actual steel plate is 3× 200 = 600 cm = 6 m, and the actual steel plate is 2.4× 200 = 480 cm = 4.8 m. The actual steel plate area is 6× 4.8 ÷ 2 = 14.4 square meters.
The above is a detailed solution, in which the value of π is probably determined or kept by yourself, and then calculated by yourself.