Primary School Mathematics Olympiad urgently needs answers! Thank you!

The original volume is 60 * 20 * 25 = 30,000 cubic centimeters, and the volume after chiseling is (60-2) * (20-2) * (25-2) = 24,012 cubic centimeters, so the volume is reduced by 30,000-24,012 = 5,988 cubic centimeters.

The volume of the box = length, width, and height.

Therefore, the original volume is 60 * 20 * 25 = 30,000 cubic centimeters, and the length, width and height after chiseling are 60-2, 20-2, 25-2, so the volume after chiseling is (60-2) * (20-2) * (25-2) = 24012 cubic centimeters.

So the volume is reduced by 30000-24012 = 5988 cubic centimeters.

Draw a diagram and get 60 * 2 * 25 = 3000 cubic centimeters 2 * 18 * 25 = 900 cubic centimeters.

60-2)*18*2=2088 cubic centimeters.

The sum of the three numbers is 5988 cubic centimeters, which is the reduced volume.

The volume of the box = length, width, and height.

So. The original volume is 60 * 20 * 25 = 30,000 cubic centimeters, and the length, width and height after chiseling are 60-2, 20-2, 25-2, so the volume after chiseling is (60-2) * (20-2) * (25-2) = 24012 cubic centimeters.

So the volume is reduced by 30000-24012 = 5988 cubic centimeters.

The volume of the box = length, width, and height.

The volume of the original cuboid stone is: 60 20 25 = 30,000 cubic centimeters, the length, width and height after chiseling are: 60-2, 20-2, 25-2, so the volume of the chiseled stone:

60-2) (20-2) (25-2) = 24012 cubic centimeters.

So the volume is reduced by 30000-24012 = 5988 cubic centimeters.

60*20*25=30,000 cubic centimeters.

60-2) (20-2) (25-2) = 24012 cubic centimeters.

Reduced by 30000-24012 = 5988 cubic centimeters.

Draw a diagram and get 60*2*25=3000 cubic centimeters.

2*18*25=900 cubic centimeters.

60-2)*18*2=2088 cubic centimeters.

The sum of the three numbers is 5988 cubic centimeters, which is the reduced volume.

Since it is any point, then assume that it is the outer center so that the distance from point P to points a, b, and c is equal, that is, EFG is the midpoint of BC, AB, and AC respectively, then it is obvious that the area of each small triangle is equal, so the area of the shadow part is half of the area of the large triangle, that is, 12 square centimeters.

I don't know if I can assume that point p is a special point, and I said that I didn't draw a general conclusion, which may not be too rigorous, but I can only give the answer like this......

Half of 24 is 12 square centimeters.

Because e, f, and g are respectively perpendicular feet.

So the area of the shaded part is equal to the blank part, respectively.

Solution: 24 2 12 (square centimeters).

1 A and B are kilometers away from Xiao Zhang, and the second time a total of 3 A and B are away from A and B villages = kilometers.

The fourth encounter walked a total of 7 distances A and B, and Xiao Zhang walked kilometers = , that is, 2 distances More than a kilometer The location of the fourth encounter is away from Village B.

1 km, with a total distance of x km;

x = y km from B at the time of the fourth encounter; Set the direction to the right as the positive direction.

y=-1, so the place of encounter is 1 km away from village B.

I'm a teacher, thank you.