# Examples for 8th grade - page 54

- Square circles

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

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

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

Tower height is 300 meters, weight 8000 tons. How high is the model of the tower weight 1 kg? (State the result in the centimeters). The model is made from exactly the same material as the original no numbers need to be rounded. The result is a three-digi - 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? - 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. - 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? - 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? - Juice box 2

Box with juice has the shape of a cuboid. Internal dimensions are 15 cm, 20 cm and 32 cm. If the box stay at the smallest base juice level reaches 4 cm below the upper base. How much internal volume of the box fills juice? How many cm below the top of the - 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? - Sisters

Sisters Zuzka Lenka and Vierka has save for a new bike. Zuzka save € 90, Lenka save € 90 and Vierka save € 82. Missing 30% gave them their mother. What is the price of the bike? - Trapezium

The area of trapezium is 35cm^{2}find its altitude if the bases are 6cm and 8cm. - Circle and hexagon

Calculate the radius of a circle whose circumference is 8.4 cm longer than the circumference of the inscribed regular hexagon. - Mother and daughter 2

The mother is 40 years older than her daughter. How old is the mother if her age is eight thirds age of daughter? - Efficiency

A certain device consumes 28 kW and delivers 14 kW. Find its efficiency. - Number

What number is 20 % smaller than the number 198? - Water well

Drilled well has a depth 20 meters and 0.1 meters radius. How many liters of water can fit into the well? - The ship

The ship went upstream speed of 20 km/h in relation to water. River flows at speed 10 km/h. After half an hour, he stopped and returned downstream to the starting point. How long it took way back when even if downstream speed of ship is 20 km/h in relation - Cleaners

Milan would clean up the room for 2.5 hours, Eric would take 10 hours. How long they swept the room together? - Painting

To paint the pool with dimensions: 2 meters depth, 3m x 4m we bought paint to 50 meters square. How many "paint" will be a waste?

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