# Examples for 8th grade - page 59

- Earth's surface

The greater part of the earth's surface (r = 6371 km) is covered by oceans; their area is approximately 71% of the Earth's surface. What is the approximate area of the land? - Tram

In the three-part tram went 109 passengers in front of others, 92 after others and in the middle half of all. How many passengers went in tram total? - Coal

If the daily consumption of 1.6 tons of coal, it is sufficient to supply the boiler for 42 days. How long is sufficient to supply when will burn only 1.2 tons of coal a day ? - Trapezoid thirds

The ABCD trapezoid with the parallel sides of the AB and the CD and the E point of the AB side if the segment DE divides the trapezoid into two parts with the same area. Find the length of the AE line segment. - Plan scale

At what scale is drawn plan of the building, where one side of the building is 45 meters long is on the plan expressed by a straight line 12 mm long. - 4 pipes

The tank flows out by 4 pipes in 6 hours 120 hl water. How much water flows out of 5 pipes of the same diameter in 14 hours? - Minute

Two boys started from one place. First went north at velocity 3 m/s and the second to the east with velocity 4 m/s. How far apart they are after minute? - Rope slack

Between two streets 20 m away give the lamp, which is in the middle and hanging 60 cm bellow the taut rope. Can be done with 20.5 meters rope? - Sines

In ▵ ABC, if sin(α)=0.5 and sin(β)=0.1 calculate sin(γ) - Brigade

On a weekly forest brigade operates 12 students. After plant one hundred spruces get x CZK, anfter one hundred pines y CZK. How many CZK got one student for one day if planted spruces 25000 and 30000 pines week? - Well

Rope with a bucket is fixed on the shaft with the wheel. The shaft has a diameter 60 cm. How many meters will drop bucket when the wheels turn 15 times? - Wheel

Diameter of motocycle wheel is 63 cm. How many times rotates wheel on roand long 1 km? - Square garden

On the plan with a scale of 1:1500 is drawn as a square garden with area 4 cm^{2.}How many meters is long garden fence? Determine the actual acreage gardens. - Sisters

Sisters Janka and Danka are saved together 220 CZK. On a trip to Janka wants to take a fifth of her savings and Danka quarter. Then they will have 50 CZK on the trip. How much money saved Janka and Danka? - New refrigerator

New refrigerator sells for 878 USD, Monday will be 25% discount. How much USD will save, and what will be the price? - Tiles

How many square tiles with the content 121 cm^{2}has to be ordered for the paving of the square room with a side length of 2.75 meters? - Hexagon = 8 parts

Divide the regular hexagon into eight equal parts. - Solutions

How much 60% solution and how much 35% solution is needed to create 100 l of 40% solution? - Three numbers

Find three numbers so that the second number is 4 times greater than the first and the third is lower by 5 than the second number. Their sum is 67. - Sugar

Sugar factory produced 938.1 tons of sugar in 1 day at 14% sugar content . How many tons of pure beet sugar factory processed in 1 day?

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