# Examples for 8th grade - page 42

- Inflow - outflow

The tank will fill by inflow for 143 minutes and empties by outflow for 150 minutes. How long take to fill tank if it is also opened the inflow and outflow? - Prism

The volume of tetrahedral prism is 2.43 m^{3}. Base of prism is a parallelogram in which a side 2,5dm and height ha = 18cm. Calculate the height of the prism. - Aircrafts

Above the town hall tower flew the plane with constant speed 592 km/h and 15 minutes later the second plane at speed of 675 km/h. How long and how far from the town hall will be aircrafts caught up? - Percentage of waste

In a square plate with side 75 cm we cut 4 same circles. Calculate the percentage of waste. - Bottles of juice

How many 2-liter bottles of juice need to buy if you want to transfer juice to 50 pitchers rotary cone shape with a diameter of 24 cm and base side length of 1.5 dm. - Stairs

Between adjacent levels are 15 stairs. If step will be 1.2 cm lower there would be 16 stairs. What is the stair height? - 6 regular polygon

It is given 6 side regular polygon whose side is 5 cm. Calculate its content area. Compare how many more cm^{2}(square centimeters) has a circle in which is inscribed the 6-gon. - Garage

There are two laths in the garage opposite one another: one 2 meters long and the second 3 meters long. They fall against each other and stay against the opposite walls of the garage and both laths cross 70 cm above the garage floor. How wide is the garag - Cars motion

From point A car start at the speed of 90 km/h. Against it departs from the point B at the same time another car at 60 km/h. For how long and where they met if the distance between A and B is 180 km? - Slope

Calculate the slope of a line that intersects points (-84,41) and (-76,-32). - Bank deposit

Ms Jana after the withdraw amount of 2,500 euros after year saving in bank. What was her deposit if the interest rate was 2.5% p.a.. - Roots

Calculate the square root of these numbers: - Wood

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

Two trains go at each other. First at speed 40 km/h and the second at speed 60 km/h. At what distance will be 30 minutes before they will meet? - Water level

The glass container has a cuboid shape with dimensions of the bottom 24 cm and 12 cm. The height of water is 26 cm. Calculate the volume of the body, which are sunk into the water if the water level rise by 3 cm. - The dam

The water reservoir is filled with first tributary for 25 hours second tributary for 35 hours. Some time were both inlets open, then a second tributary closed and the tank was filled in four hours. What time water flowed from both tributaries? (Expressed i - The cylindrical container

The container has a cylindrical shape the base diameter 0.8 meters has a content area of the base is equal to the content area of the shell. How many full liters of water can be poured maximally into the container? - Workers

Ten workers must pave road street for 22 working days. After four days were for speeding up work added two more workers. a) After how many work days now workers completes the paved road? b) How many working days it took a total paved road? - Lamp cone

Calculate the surface of a lamp shade shaped of a rotary truncated cone with base diameter 32 cm and 12 cm and height 24 cm. - Map scale

Garden has on plan on a scale of 1: 150 width 22 cm and length 35 cm. What is the real area of the garden?

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