# Examples for 8th grade - page 30

- Field with vegetables

Field planted with vegetables has shape of a rectangular isosceles triangle with leg length of 24 m. At the vertices of the triangle are positioned rotating sprinklers with a range of 12 m. How much of the field sprinkler doesn't irrigated? - Number

Is number 4.764023 irrational? - Addends

Number 389 divide into the two addends that the first was 6 greater than 60% of the second. Determine these addends. - Trapezoid ABCD

Calculate the perimeter of trapezoid ABCD if we know the side c=25, b=16 which is also a height and side d=27. - Map 2

At what scale is made map if the distance 6.8 km corresponds on the map segment 4 cm long? - Cars plates

How many different licence plates can country have, given that they use 3 letters followed by 4 digits? - The body

The body on the figure consists of cubes with an edge length 10 cm. What surface has this body? - Complete construction

Construct triangle ABC if hypotenuse c = 7 cm and angle ABC = 30 degrees. / Use Thales' theorem - circle /. Measure and write down the length of legs. - Building base

Excavation for the building base is 350x600x26000. Calculate its volume in m^{3.} - Mother and daughter

Three years ago mother was three times older than daughter. After nine years she will be only twice old. How old is mother (and daughter)? - Mountain railway

Height difference between points A, B of railway line is 38.5 meters, their horizontal distance is 3.5 km. Determine average climb in permille up the track. - Work

First paver pave pavement for 33 hours. Second for 24 hours. Started first paver and after 5 hours, join the second. How long will they finish pavement? - Cube and water

How many liters of water can fit into a cube with an edge length of 0.11 m? - Swing

A child weighing 12 kg is sitting on a swing at a distance of 130 cm from the axis of rotation. How far away from the axis of rotation (center) must sit down his mother weighs 57 kg if she wants to be swing in balance? - Sprayers

The vineyard can be sprayed first sprayer in 5 hours and with the second in 7 hours. How long would it take if we use sprayers both at once? - 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? - Bath

In the bath is 30 liters of hot water. Then added 38 liters of cold water at temperature of 17 °C decreased temperature of water to 48 °C. What was the initial temperature of the hot water? - Gasholder

The gasholder has spherical shape with a diameter 23 m. How many m^{3}can hold in? - Paul and Honza

Honza went to chat on a bike without a break 3.0 hours. Paul the same way without breaks 30 minutes longer. The difference between the speeds of the two boys was the one kilometer per hour. How fast was Paul, if you know that the speed of the boys did not. - Workman - shift

The worker produces 300 components per shift. How many components would be produced in 18 shift, if his performance gradually increased every shift by 3 components?

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