A cuboid container, with a bottom area of 4 square decimeters and a height of 10 cm, contains 5 cm high water. Now, a stone is immersed in the water and the water level rises I hope it can be finished today (10.7). It's urgent

A cuboid container, with a bottom area of 4 square decimeters and a height of 10 cm, contains 5 cm high water. Now, a stone is immersed in the water and the water level rises I hope it can be finished today (10.7). It's urgent

40 × (8-5) = 120 (cm3)

A cuboid container, with a bottom area of 4 square decimeters and a height of 10 cm, contains 5 cm high water. First, immerse a stone in the water, and the sleep rises
What's the volume of this stone at 8 cm? (fast bonus points)

5 cm = 0.5 decimeter, 8 cm = 0.8 cm
4 * (0.8-0.5) = 1.2 (square decimeter) = 1200 (square centimeter)
A: the volume of this stone is 1200 square centimeters

The weight of pile a is 60% of that of pile B
If 4 tons of sand is taken from each of the two piles, the pile a is 40% of that of the team B. how many tons of yellow sand are there in each pile a and B,

B (4-4 × 40%) / / 60% - 40%
=2.4÷20%
=12 tons
A 12 × 60% = 7.2 tons

Try to find out the relationship between a and B that makes LG (a + b) = LGA + LGB (a > 0, b > 0) hold, a = f (b) =?

lg(a+b)=lga+lgb=lgab
a+b=ab
ab-a=b
a(b-1)=b
So a = B / (B-1)

There are 400 male workers in a factory, which is more than the number of female workers, accounting for 1 / 9 of the total number of the whole factory. How many workers are there in the whole factory

400 △ [(1-9 / 1) △ 2 + 9 / 1]
=400 △ 5 / 9
=720 (person)
A: there are 720 employees in the factory

Given 2x + 3Y = 6, find the maximum value of XY

x=(6-3y)/2
xy=(6-3y)y/2=3y-3y^2/2
=-(3/2)(y^2-2y)
=-(3/2)^2(y-1)^2+3/2
So when y = 1 and x = 3 / 2, the maximum value of XY is 3 / 2

In 2012, the () Olympic Games were held in London, England

30

If the square of X + XY + y = 14, the square of X - XY + y = 28, find the value of X + y
It's due tomorrow! Thank you very much!

X ^ 2 + XY + y ^ 2 = 14 (1) x ^ 2-xy + y ^ 2 = 28 (2) add the two formulas to get 2 (x ^ 2 + y ^ 2) = 42, that is, x ^ 2 + y ^ 2 = 21 (3) subtract the two formulas to get 2XY = - 14 (4) because (x + y) ^ 2 = x ^ 2 +

A class of a students participate in tree planting activities, including B boys (b < a), if only completed by boys, each need to plant 15 trees; if only completed by girls, each need to plant trees______ A tree

The total number of trees planted is 15b, and the number of girls is A-B, so each girl needs to plant 15ba − B trees

Does the square root have to be an integral number?

Not necessarily: square root: & nbsp; & nbsp; & nbsp; & nbsp; √ A & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; square root of a; open cube: & nbsp; & nbsp; & nbsp; a ^ (1 / 3) & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; cube root of a