# Examples for 8th grade - page 30

1. Two diggers
There are two diggers. One digger digs a pit 46 hours second gidding 2 times faster. a) how long took to dig a pit second digger b) how long took dig together
2. Internal angles
The ABCD is an isosceles trapezoid, which holds: |AB| = 2 |BC| = 2 |CD| = 2 |DA|: On its side BC is a K point such that |BK| = 2 |KC|, on its side CD is the point L such that |CL| = 2 |LD|, and on its side DA the point M is such that | DM | = 2 |MA|. Dete
3. Bomber
Bomber flies 10 km at 600 km/h. At what horizontal distance from the target, must pilot drop the bomb to hit the target? Don't care about air resistance and consider the gravitational acceleration g=9.81 m/s2.
4. Trapezoid
Area of trapezoid is 135 cm2. Sides a, c and height h are in a ratio 6:4:3. How long are a,c and h? Make calculation...
5. Divers
20-member group of divers carries the air for 15 hours of diving. 4 members of the expedition sick or wasn't came. How many hours is sufficient air to other divers?
6. Lorry
The lorry was loaded with 18 boxes of 15 kg. How many boxes with weight 18 kg can be loaded, if total load must be same?
Grandson with grandpa they counted how many years have together. Their product is 365. How many years is the sum of their years.
8. 30-60-90
The longer leg of a 30°-60°-90° triangle measures 5. What is the length of the shorter leg?
9. Iron fence
One field of iron fence consists of 20 iron rods with square cross-section of 1.5 cm side and a long 1 meter. How much weight a field if the density of iron is 7800 kg/m3.
10. Two cars
From the town A to town B started two cars. The first at 7:00 at average speed 60 km per hour, the second at 10:00 at average speed 100 km per hour. The first car will not stay in B, and on the way back meet the second car at half way from A to B. At what.
11. Racer
The first racer run at a speed 20 m/s and is 750 meters before the finish and ahead 79 meters before second competitor. At what speed must run the second racer to catch first racer at the finish line?
12. Strawberries
Father collects strawberries himself in 4 hours, son in 14 hours. How long will it take them along when dad comes to help son collect strawberries after 3 hours?
13. Sawdust
How many cubic centimeters of wood sawdust is created by cut the tree trunk with a diameter of 66 cm and when the gap width is 5 mm?
14. Pyramid
Cuboid ABCDEFGH has dimensions AB 3 cm, BC 4 cm, CG 5 cm. Calculate the volume and surface area of a triangular pyramid ADEC.
15. Chicken
I threw three chicken for a handful of grains and I noticed that it eat in a ratio of 8:7:6 and two of them grabbed 156 grains. How many grains have fought that chicken?
16. Unions
Calculate how much money per year would go to the treasury of unions if 218 thousand employee join unions with an average net salary of 407 euros and if memberhip in union cost 1% of the net monthly salary.
17. Painter 3
Dad want to paint wall high 250 cm wide and 230 cm with wallpaper. How many meters must buy wallpaper if wallpaper width is 60 cm?
18. Cube and water
How many liters of water can fit into a cube with an edge length of 0.11 m?
19. Flowerbed 2
Around the square flower bed in a park is sidewalk 2 m wide. The area of ​​this sidewalk is 243 m2. What is the area of the flowerbed?
20. Cuboids in cube
How many cuboids with dimensions of 6 cm, 8 cm and 12 cm can fit into a cube with side 96 centimeters?

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