In a hurry, I will mention a primary school graduation application question

The surface area of the cuboid is the sum of the areas of the six faces, so to cut into two cuboids with the same shape and size, the sum of the surface areas of the two cuboids needs to be the largest, the length is 10 cm, the width is 8 cm, the height is 3 cm, the sum of the surface area is (10 * 8 + 10 * 3 + 8 * 3) * 2 * 2 = 536 (square centimeters), the sum of the surface area needs to be truncated at least is 8 cm long, the width is 5 cm, the height is 6 cm of two cuboids, the sum of the surface area is (8 * 5 + 8 * 6 +5*6)*2*2=472 (square centimeters).

The surface area of the two truncated boxes is equal to.

The surface area of the original box plus twice the area of the cross-sectional face.

The surface area of the original cuboid 2*(10*8+8*6+6*10)=376 has three cases:

Old. The maximum is 536

The smallest is 472

The largest is to cut the 10 8 side, and there are two 10 8s, so it must be the largest.

The smallest is to cut the area of 6 8, there are only two 6 8, so it must be the smallest.

It is expressed by the equation as:

Maximum: 6 2 = 3 cm, indicating the height after incision, (10 8 + 10 3 + 8 3) 2 2 = 536 cm

Minimum: 10 2 = 5 cm, which is the height after the incision, (5 8 + 5 3 + 3 8) 2 2 = 316 cm

3÷（4+3） 3/7-1/3=2/21=3÷7 (4-3)÷7=1÷7=1/7

Three-sevenths 20 2 21x1 7=20x21 2x1 7

210x1/7

30 (km).

Adopt it, please, please.

A and B ride bicycles at the same time in the opposite direction, the ratio of A and B is 3:4, it is known that A has traveled the whole course of 1 3, there are still 20 kilometers away from the place of meeting, how many kilometers is A less than B when they meet?

The ratio of the number of A and B is 3:4, so when they meet, the whole journey of line A is 3 7, the whole journey of line B is 4 7, and the whole course of A is 1 7 more than that of line B;

Let the whole journey be y, and A is 20km away from the place of meeting, so there are 3 7y-1 3y=20 and y=210

1/7y=30km

So A travels 30km more than B

The ratio of travel between A and B at the time of meeting is: 3:4

That is, line A: 3 7, line B: 4 7

The distance is: 20 (3 7-1 3) = 210 km, A travels less than B when they meet: 210 * (4 7-3 7) = 30 km.

Solution: 56 ml = 56 cubic centimeters, then the bottom area of the container is 56 8 = 7 (square centimeters).

Since the height of the water surface in the container is only 4 cm after the cylinder is removed, the volume of the overflow water is 7 * (8-4) = 28 (cubic centimeters), that is, the volume of the part of the cylinder immersed in water is 28 cubic centimeters.

Due to the height of the cylinder and the height of the container, the volume of the cylinder immersed in water is not all the volume of the cylinder, but only a part of the volume of the cylinder.

So the height of the cylindrical part immersed in water is equal to the height of the container is 8 cm, then the bottom area of the cylinder is 28 8 = square centimeters), so the volume of the cylinder is cubic centimeters).

Combined, it is: 56 ml = 56 cubic centimeters.

56 8 = 7 (square centimeters).

7*(8-4)=28 (cubic centimeters).

28 8 = square centimeters).

cubic centimeters) A: The volume of a cylindrical rod hanging is cubic centimeters.

56 ml = 56 cubic centimeters.

56 2 8 = square centimeters.

Cubic centimetre.

56 8 = 7 square centimeters (base area of the volume of the cylinder. ）

7*4=28 cubic centimeters (the volume of spilled water, that is, the volume of the sticks.) ）

A: The volume of the wooden stick is 28 cubic centimeters.

Let 2 workshops be a (a-48) x 3 2-14 = (a + 15) x 4 5 a = 140 1 workshop is 138 3 workshop 124 total number of people (140 + 138 + 124) x 5 3 = 670