# Examples for 8th grade - page 54

- The field

The player crossed the field diagonally and walked the length of 250 m. Calculate the length of the field, circumference if one side of field 25 meters. - 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? - 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? - 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. - Middle segment

In a triangle ABC with the side /AB/ = 24 cm is constructed middle segment /DE/ = 18 cm parallel to the side AB at a distance 1 cm from AB. Calculate the height of the triangle ABC to side AB. - 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? - 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 - Cuboid walls

Calculate the volume of the cuboid if its different walls have area of 195cm², 135cm² and 117cm². - Efficiency

A certain device consumes 93 kW and delivers 77 kW. Find its efficiency. - 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? - Fewer than 500 sheep,

There are fewer than 500 sheep, but if they stand in a double, triple, quadruple, five and sixth order, one sheep will remain. But they can stand in the seventh order. How many are sheep? - Square circles

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

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

Calculate the radius of a circle whose circumference is 6.8 cm longer than the circumference of the inscribed regular hexagon. - 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. - 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? - 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 - Water well

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

What number is 24 % smaller than the number 51?

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