In a cuboid water tank 15 decimeters long and 12 decimeters wide, there is water 10 decimeters deep. Now a cube sinks into the water, and the water The surface rises to 11. Find the volume of the cube

In a cuboid water tank 15 decimeters long and 12 decimeters wide, there is water 10 decimeters deep. Now a cube sinks into the water, and the water The surface rises to 11. Find the volume of the cube

Just calculate the volume of the water surface after rising, and then subtract the original volume
15*12*11.5-15*12*10=2070-1800=270（cm³）

A cuboid water tank is 50cm long, 40cm wide and 30cm high. It contains water with a depth of 20cm. A cube ingot with an edge length of 0.1M is put in
A cuboid water tank is 50 cm long and 40 cm wide. It contains water with a depth of 20 cm. How many centimeters is the water depth after a cube ingot with 0.1 meter edge length is put in?

0.1 M = 10 cm
50 * 40 * 20 = 40000 CC
10 * 10 * 10 = 1000 CC
40000 + 1000 = 41000 CC
41000 / 50 / 40 = 20.5cm
A: the water depth is 20.5cm

Given that P (2a-8,2-a) is a point in the third quadrant, and its abscissa and ordinate are integers, what is the coordinate of P?

2a-8＜0
2-a＜0
That is 2 < a < 4
That is, a = 3
P（-2,-1）

If f (x) is an odd function with period 3 and f (- 1) = 2, then f (3) + F (4)=

=f(3)+f(3+1)=0+f(1)=-2 f(X)=-f(-X)

Monotonicity of the analytical formula analysis, increase function addition and subtraction function is equal to what function, increase function multiplication and subtraction function is equal to what function

Not necessarily
y1=2x
y2=-x
y3=-3x
Then Y1 increases and the last two decrease
Obviously, Y1 + y2 = x is increasing
And Y1 + Y3 = - x decreases
However, both y1y2 and y1y3 are quadratic functions and have no monotonicity on R

Given the slope k = 3 and the intercept on the x-axis is 1 / 2, the equation of the straight line is obtained

y=3(x-1/2)

A 100 point math problem
Given that a = {x | x = 28m + 20n, m, n belong to Z}, B = {x | x = 12m + 18N, m, n belong to Z}, find the smallest positive integer belonging to the intersection of a and B, and find a group of M, n values in a and B at this time

If we study a, x = 28m + 20n = 4 (7m + 5N), we can prove (if we need to supplement) because 7 and 5 are coprime, so when m, n takes all integers, 7m + 5N also takes all integers. So set a represents the multiple of 4 (including positive number, negative number and zero). If we study B, x = 12m + 18N = 6 (2m + 3n), because 2 and 3 are coprime, so when m, n takes all integers

A group of applied problems of inequality in junior high school
A type a pump that can pump 1.1 tons of water per minute can be used to pump water from the pool, which can be finished in half an hour;
If B type pump is used, it is estimated that 20 to 22 points can be finished. B type pump is better than a type pump
How many tons more water does the water machine pump per minute?
What does "every minute" mean? To write a detailed process. To the equation of one variable inequality

Suppose type B pumps about X tons more water per minute than type A
20(1.1+x)30*1.1 ⑵
From (1): x0.4
So the solution set of inequality system is 0.55 > x > 0.4
A: about 0.4-0.55 tons more water per minute
My sister's solution should be right. ADA, believe me

If y = x + 4 intersects with X axis at a, intersects with y axis at B, and 0 is the origin, then the area of △ AOB

Substituting into the equation: a = - 4, B = 4, so the area is 1 / 2 * (- 4) * 4 = 8

If the function y = f (x) satisfies f (t-x) = f (x), then the axis of symmetry of the function is

The axis of symmetry is x = t / 2