# Direct relationship - 8th grade (13y) - math problems

#### Number of problems found: 178

- Trapezium

The length of the base and the height size of the base of the trapezium is at ratio 5:3:2, the content area of the trapezium is 128 cm^{2}. Calculate the length of the base and the height of the trapezoid. - Scale

The swimming pool is long 110 m and 30 m wide. The plan of the city is shown as a rectangle with an area 8.25 cm^{2}. What scale is the city plan? - Chocolate

I have a box of chocolate - white, milk and dark. The ratio of white to milk with dark is 3: 4. The ratio of white and milk to dark is 17: 4. Calculate what is the ratio between white, milk, dark chocolate. - Sides od triangle

Sides of the triangle ABC has length 4 cm, 5 cm and 7 cm. Construct triangle A'B'C' that are similar to triangle ABC which has a circumference of 12 cm. - Blueberries

5 children collect 4 liters of blueberries in 1.5 hours. a) How many minutes do 3 children take 2 liters of blueberries? b) How many liters of blueberries will be taken by 8 children in 3 hours? - Nectar

Nectar collected by bees contains 70% water. From the nectar of the some process produces honey which contains 19% water. How many kg of nectar bees need to collect to make 1 kg of honey? - Pizza

Pizza with a diameter 50 cm have weight 559 g. What diameter will have a pizza weighing 855 g if it is make from the same cloth (same thickness....) and same decorated? - Bathroom

How many CZK we pay for lining the perimeter walls of the bathroom with rectangular shape with dimensions 3.5 m and 4 m, high 1.5 m if 1 square m tile cost 300 CZK? - Twelve

Twelve students work on a week forestry brigade. One hundred spruces will receive x CZK, one hundred pine y CZK. How many receive each one students did in one day if they planted a total of 25,000 spruces per week and 30,000 pine trees? Express by express - Cooling liquid

Cooling liquid is diluted with water in a ratio of 3:2 (3 parts by volume of coolant with 2 volumes of water). How many volumes of coolant must be prepared for a total 0.7 dm^{3}(liters) of the mixture? - Air thermal

Imagine that a unit of air rises at 3000 meters high, if temperature decreases 6 degrees celcius for every 1000 meter, what will be its temperature at 1400 meters, 2000 meters, 2500 meters and when it reaches the 3000 meter elevation. Starting temperature - Five inlets

The tank can be filled with five equally powerful inlets. If the tank is filled by four of these inlets, it takes a total of 30 minutes to fill one-third of the tank. How many minutes does it take to fill an empty tank if it is filled with all five inlets - Book reading

Susan thought, "If I read 15 pages a day, I will read the whole book in 8 days. “How many pages would she have to read a day if she wanted to finish the book on the 6th day from the start of reading? And how many pages does the book have? - Leveling

Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 15 m^{2}to the "height" 6 mm if consumtion is 1.5 kg per square meter and millimeter thickness. - Land area

A land area of Asia and Africa are in a 3: 2 ratio, the European and African are is 1:3. What are the proportions of Asia, Africa, and Europe? - Seawater

Seawater has a density of 1025 kg/m^{3}, ice 920 kg/m^{3}. 8 liters of seawater froze and created a cube. Calculate the size of the cube edge. - Trapezoid - intersection of diagonals

In the ABCD trapezoid is AB = 8 cm long, trapezium height 6 cm, and distance of diagonals intersection from AB is 4 cm. Calculate the trapezoid area. - ŽSR

Calculate fixed annual personnel costs of operating monorail line 118 km long if every 5 km is a station, which serves three people - one dispatcher and two switchmen in 4-shift operation. Consider the average salary of the employee 885 €. - Fixed expenses 2013

Since 2013, the Slovak government plans to tax more small one person businesses. Instead of fixed expences 40% will be fixed expences 40% of gross income up to 420 Eur. Calculate what percentage of fixed expences will in 2013 pays from gross income 1569 E - Shadow of tree

Miro stands under a tree and watching its shadow and shadow of the tree. Miro is 180 cm tall and its shade is 1.5 m long. The shadow of the tree is three times as long as Miro's shadow. How tall is the tree in meters?

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