# Examples for 8th grade - page 75

1. Flowerbed
In the park there is a large circular flowerbed with a diameter of 12 m. Jakub circulated him ten times and the smaller Vojtoseven times. How many meters each went by and how many meters did Jakub run more than Vojta?
2. Simply equation
Solve this equation for x: ?
3. Cuboid - ratios
The sizes of the edges of the cuboid are in the ratio 2: 3: 5. The smallest wall have area 54 cm2. Calculate the surface area and volume of this cuboid.
4. Rhombus 4
Circumference of the rhombus is 44 cm, its height is 89 mm long. Calculate its content area.
5. Savings and retirement
The older sibling has saved 44% more euros than the youngest, which represents 22 euros. How many euros older brother has saved ?
6. Donuts
In the dining room at one table sit Thomas, Filip and Martin. Together they eat 36 donuts. How many donuts eaten everyone, when Filip ate twice as much as Thomas and Martin even half over Filip?
7. Joshka
Joshka had € 15. Mama took him 15%. How many had left?
Kamila wants to change the password daliborZ by a) two consonants exchanged between themselves, b) changes one little vowel to such same great vowel c) makes this two changes. How many opportunities have a choice?
9. Unknown number 24
f we add 20, we get 50% of its triple. What is this unknown number?
10. Buttons
Shirt has 6 buttons, blouse has 4 buttons. All buttons are 176. Shirts and blouses are together 36. How many are the shirts and blouses?
11. Fuel economy
How many kilometers is sufficient petrol in the cylinder fuel tank with a diameter 40 cm and the base of tank length 1 m, when it is filled to 60% and if the car consume 15 liters per 100 km?
12. Coins
Denis and Zdeno together have 97 coins. If Denis had 4 coins less than he has now, the number of the coins would be in the ratio 14: 17. Determine the number of coins owned by Denis and Zdeno.
13. Disc
Circumference of the disk is 78.5 cm. What is the circumference of the circular arc of 32° on the disc?
14. Bath salts
Bath salt A weighs 900 grams and costs 36,40 CZK. Bath Salts B weighs 1000 grams, but costs 85 CZK. How much is a bath salt A cheaper than B one?
15. Pharmacy
The pharmacy add to 3 liters of 95-percent alcohol 5 liters of 38.04 percent alcohol. How many percent pharmacy got?
16. Percent
Calculate how many % is the number 26.25 less than the number 105.
17. Percentage - fractions
About what percentage we must increase number 1/6 to get number 1/3?
18. Cube surface area
The surface of the cube was originally 216 centimeters square. The surface of the cube has shrunk from 216 to 54 centimeters sq. Calculate how much percent the edge of the cube has decreased.
19. Flowerbed
Family cultivated tulips on a square flower bed of 6 meters. Later they added the square terrace with a side of 7 meters to their house. One vertex of the terrace lay exactly in the middle of a tulip bed, and one side of the terrace divided the side of the
20. Circle - simple
Calculate the area of a circle in dm2, if its circumference is 31.4 cm.

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