A 6-decimeter-high cylindrical bucket is filled with half a bucket of water. After 12 kg of water is poured out, the remaining water just accounts for 30% of the bucket's volume. The bottom area of the bucket A cylindrical bucket with a height of 6 decimeters is filled with half a bucket of water. After 12 kg of water is poured out, the remaining water just accounts for 30% of the bucket volume. What is the bottom area of the bucket?

A 6-decimeter-high cylindrical bucket is filled with half a bucket of water. After 12 kg of water is poured out, the remaining water just accounts for 30% of the bucket's volume. The bottom area of the bucket A cylindrical bucket with a height of 6 decimeters is filled with half a bucket of water. After 12 kg of water is poured out, the remaining water just accounts for 30% of the bucket volume. What is the bottom area of the bucket?

That is to say, there is 50% water at the beginning, and the rest is 30%, so 12 kg is 20%, so the total water mass = 12 / 20% = 60 kg. The water density is 1 g / cm3, so the barrel volume = water mass / water density = 60000 / 1 = 60000 cm3 = 60 cubic decimeter. So the bottom area = 60 / 6 = 10 cubic decimeter
I don't know what grade you are in. Have you ever studied physics

A far cylindrical iron sheet bucket without cover has a bottom area of 30cm in diameter and a height of 50cm. To make such a bucket, at least iron is needed

The diameter of the bottom area of the tin bucket is 30cm
30 × 3.14 = 94.2 (CM)
Its lateral area is:
94.2 × 50 = 4710 (cm2)
So its radius is:
30 △ 2 = 15 (CM)
Its bottom area is:
15 × 15 × 3.14 = 706.5 (cm2)
Therefore, making such a bucket requires at least iron sheet:
4710 + 706.5 = 5416.5 (cm2)
5416.5 sq cm = 54.165 sq m

The volume of a bucket is 24 cubic decimeters, the bottom area is 7.5 square decimeters, and there is a hole 0.7 decimeters away from the bucket mouth. Now the bucket can hold water at most______ Kg. (1 kg per cubic decimeter of water)

Now this bucket can hold water: 1 × (24-7.5 × 0.7), = 1 × (24-5.25), = 18.75 (kg); answer: now this bucket can hold water up to 18.75 kg. So the answer is: 18.75