# Examples for 8th grade - page 28

- Balls

Ping pong balls have a diameter of approximately 3 cm. They are sold in boxes of 3 pieces: each box has the shape of a cuboid with a square base. The balls touch the walls of the box. Calculate what portion of the internal volume of the box is filled wit - Salary

Mr. Johnson's had monthly salary 966 USD since the beginning of year. From which month his salary was increased by 74 USD, when in year earned 11814 USD (enter as a number from 1 to 12)? - Lead cube

Calculate the edge of the cube made from lead, which weighs 11 kg. The density of lead is 11341 kg/m^{3.} - Two numbers

Find two numbers whose difference and ratio is 10. - Cows

Agricultural cooperative has increased the number of housed cows by 14% to 285 units. By how many cows increased agricultural cooperative the number of cows? - Cacao

Cacao contains 34% filling. How many grams of filling are in 130 g cacao. - Washing mashine

Family buy a washing machine for 350e. Cash paid 280e. What percentage of the total price must still pay the washer? - Grandson and granddad

Grandson with grandpa they counted how many years have together. Their product is 365. How many years is the sum of their years. - Polygon 42

Which polygon has 42 more diagonals than sides? - Inscribed triangle

To a circle is inscribed triangle so that the it's vertexes divide circle into 3 arcs. The length of the arcs are in the ratio 2:3:7. Determine the interior angles of a triangle. - Theatro

Theatrical performance was attended by 480 spectators. Women were in the audience 40 more than men and children 60 less than half of adult spectators. How many men, women and children attended a theater performance? - Parallelogram

Parallelogram has sides lengths in the ratio 3: 4 and perimeter 2.8 meters. Determine the lengths of the sides. - Wood

Wood contains 12% water. 1 m^{3}of wood weighs 650 kg. How many liters of water it contains? - Cargo

Weight of cargo car is 761 kg. Weight of car is 23% of the total weight of car+cargo. What is the weight of the cargo load? - Freight and passenger car

The truck starts at 8 pm at 30 km/h. Passenger car starts at 8 pm at 40 km/h. Passenger arrives in the destination city 1 hour and 45 min earlier. What is the distance between the city of departure and destination city? - Three workers

Three workers were rewarded CZK 7200 and the money divided by the work they have done. First worker to get twice than the second, the second three times more than the third. How much money each worker received? - Unknown integer

Find the smallest integer that: divided by 2, the remainder is 1 divided by 3 the remainder is 2, divided by 4 remainder is 3, ... divided by eight reminder is 7, by 9 reminder is 8. - Glass

Peter broke the window glass with size 110 cm and 90 cm. 1 square meter of glass costs 8 Euro. How much money is need to pay for a new glass? - Leveling

Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 28 m^{2}to the "height" 12 mm if consumtion is 1.7 kg per square meter and millimeter thickness. - Flowerbed

On the flowerbed was planted 310 flowers - pansies and crayons. During the first week wilts quarter of pansies and an eighth crayons, which is 20% of all flowers. How many pansies were planted on the flowerbed?

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