# Examples for 8th grade - page 99

1. Triangular prism
Calculate the surface of a regular triangular prism with a bottom edge 8 of a length of 5 meters and an appropriate height of 60 meters and prism height is 1 whole 4 meters.
2. The coil
How many ropes (the diameter 8 mm) fit on the coil (threads are wrapped close together) The coil has dimension: the inner diameter 400mm, the outside diameter 800mm and the length of the coil is 470mm
3. Inlet and outlet
The pool has a capacity of 50 hl. The inlet pipe flows in 1 minute 1.25 hl, and the waste pipe outlet is draining the full pool in 50 minutes. How long will take the empty the full pool when both the inlet and outlet are opened at the same time?
4. Two workers
The first worker would himself completed the work in 8 hours, the other in 6 hours. After two hours of joint work left the first worker to a doctor and other completed work himself. How many hours worked the other worker himself?
5. Viju
viju has 40 chickens and rabbits. If in all there are 90 legs. How many rabbits are there with viju??
6. Five inlets
The tank can be filled with five equally powerful inlets. If the tank is filled by four of these inlets, it takes a total of 30 minutes to fill one-third of the tank. How many minutes does it take to fill an empty tank if it is filled with all five inlets?
7. Area of garden
If the width of the rectangular garden is decreased by 2 meters and its length is increased by 5 meters, the area of the rectangle will be 0.2 ares larger. If the width and the length of the garden will increase by 3 meters, its original size will increas
8. Work
The first worker would need less than 4 hours to complete the task than the other worker. In fact, both workers worked for two hours together, then the first worker did the remaining work himself. In what proportion should the remuneration of the workers b
9. Cube surface and volume
Find the surface of the cube with a volume of 27 dm3.
10. The tank
The tank had 9 inflows to be filled in 21 days. After 9 days, 3 trips out. How many days did the remaining 6 tributaries fill the tank?
11. Spending
If spends 25% of my net pay of \$922.28 on entertainment. How much money is that?
12. Right triangle
Calculate the length of the remaining two sides and the angles in the rectangular triangle ABC if a = 10 cm, angle alpha = 18°40'.
13. Big cube
Calculate the surface of the cube, which is composed of 64 small cubes with an edge 1 cm long.
14. 7 digit number
If 3c54d10 is divisible by 330, what is the sum of c and d?
15. Flowerbed
Ondra digs the bed in 20 minutes. Cuba in 30 minutes. For how long do they dig together?
16. Ratio of sides 2
The ratio of the side lengths of one square to another is 1:2. Find the ratio of the area of the two squares.
17. Bricks pyramid
How many 50cm x 32cm x 30cm brick needed to built a 272m x 272m x 278m pyramid?
18. The painter
In order for the painter to get the desired color, he must mix green and yellow in a ratio of 4: 7. If it has 28 l of green color, how many liters of yellow color should he add? How many liters of mixed color does he get?
19. Budget plan
In the construction of the building, the planned budget exceeded 13%, which was 32,500 euros. How many euros cost built the building?
20. Body diagonal
Calculate the length of the body diagonal of the 6cm cube.

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