# Grade - examples - page 91

- Arithmetic average

The arithmetic mean of the five numbers is exactly 8. The sum of these four numbers is 30. What is the fifth number? - Sputnik

The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800 km/h. How long would it take circle the earth round? - The city

In the city is 2/4 of women married to 3/4 men. What percentage of townspeople is single (not married)? - Square circles

Calculate the length of the described and inscribed circle to the square ABCD with a side of 5cm. - Pipe

Steel pipe has a length 2.5 meters. About how many decimetres is 1/3 less than 4/8 of this steel pipe? - Saw

Blade circular saw with a diameter 42 cm turns 825 times per minute. Expresses his cutting speed in meters per minute. - Welders

Welder do the job for six hours, the second one for 8 hours. How long do the job third welder if all together can do job in 2 hours? - Concrete tank

How many m^{3}of concrete is in the tank shape of a cuboid with dimensions of 2000 cm and 5.6 meters and 70 dm, if the concrete takes up 3/7 of the tank? - Rhombus

One angle of a rhombus is 136° and the shorter diagonal is 8 cm long. Find the length of the longer diagonal and the side of the rhombus. - Mr. John

Mr. John wants to buy winter apples Spartan. There are two ways to buy: 1) buy apples at the marketplace, where 1 kg costs 15 CZK. 2) Bring the car to the agricultural farm, where the apples are sold after 9 CZK per kilogram. However, he must pay CZK 150. - Tubes

Iron tubes in the warehouse are stored in layers so that each tube top layer fit into the gaps of the lower layer. How many layers are needed to deposit 100 tubes if top layer has 9 tubes? How many tubes are in bottom layer of tubes? - Traffic laws

Under traffic regulations, car lights can illuminate the road up to a maximum of 30 m. To check the reach of the dipped-beam lights of their car, Peter stopped car at 1.5 m from the wall. The dipped-beam headlights are 60 cm high. At what height on the wa - The creek

Workers cleaned the creek within 3 days. The first day cleanse one-fifth the length of the creek, the next day 40% of the length of the stream and the third day 8 km length of the creek. How long is a creek? - Purchase

Three buyers pay € 468. The first paid 3-times more than second, third half over second. How many euros paid each of them? - Surveyor

Calculate the area of what may vary rectangular, if it focused by surveyor and found the dimensions 18 x 15 m while in each of the four joint points can be position deviation 25 cm? - Digits of age

The product of the digits of Andrew age as 6 years ago and not equal to 0. Andrew age is also the smallest possible age with this two conditions. After how many years will be the product of the digits of Andrew age again the same as today? - 100 %

How much is 100%, if 17 % is 1169? - Equation

How many real roots has equation ? ? - Three vectors

The three forces whose amplitudes are in ratio 9:10:17 act in the plane at one point so that they are in balance. Determine the angles of the each two forces. - James

James paints a fence. If every day instead of 14 planks painted 16 would be done on one day earlier. How many of planks has a fence altogether?

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