Examples for 8th grade

Every day 7 pages
Adelka reads the book every day 7 pages. When she reads one more page a day she will read it three days earlier. How long will Adelka read a book? How much does a book of pages have?
Two workers
Two workers make 138 parts/items. The first one produces 30% more than the second. How many items will each produce?
Square prism
Calculate the volume of a square prism of high 2 dm wherein the base is: rectangle with sides 17 cm and 1.3 dm
Baker
The baker makes from 10 kg of flour 12 kg dough. How much flour he need to make a 100 kg dough?
Quadrangular prism
The quadrangular prism has a volume 648 cm³. Trapezoid which is its base has the dimensions bases: a = 10 cm, c = 5 and height v = 6 cm. What is the height of the prism?
Sea water
One tonne of sea water contains 25 kg of salt. How many tonnes of sea water need to be evaporated to obtain 1 tonne of salt?
Oil tank and pipes
The underground oil tank can be filled by two oil pipelines. The first is filled in 72 hours and the second in 48 hours. How many hours from the moment when first pipeline began to fill the oil is it necessary to start filling it with the second to fill i
Mr and Mrs
Mr. Calda and Mrs. Cald have a total of 139 years. How many years have when we know that Mr. Calda is 9 years older than Mrs. Cald
Earth's diameter
The Earth's diameter on the equator is approximately 12750 km. How long does the Gripen flyover the Earth above the equator at 10 km if it is at an average speed of 1500 km / h?
The tram
The tram is moving with acceleration a = 0.3m/s2. How long it will pass the first meter of track? How long does it take 10 meters. What is its speed at the end of the 10 meters track?
Flowerbed
The flowerbed has a length 3500mm and a width 1400mm. How many foil is needed to covers the flowerbed? How many m² of foil was consumed for its production (add 10% of the material to the joint and waste)? How many liters of air is inside the enclosure? (
Volume increase
How many percent will increase in the pool 50 m, width 15m if the level rises from 1m to 150cm?
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?
Hydrostatic force
What hydrostatic force is applied to an area of 30 cm² in water at a depth of 20 m? (Water density is 1000 kg/m3)
Driver
The driver of the supply car reckoned that at the average speed of 72 km/h arrives to the warehouse for 1 1/4 hours. After 30 km however unintentionally drove to the gas station and have ten minutes delay. At what average speed would have to go the rest
Forces on earth directions
A force of 60 N [North] and 80 N [East] is exerted on an object wigth 10 kg. What is the acceleration of the object?
Sphere radius
The surface of the sphere is 60 cm square. Calculate its radius; result round to tenth of cm.
Right triangle trigonometrics
Calculate the size of the remaining sides and angles of a right triangle ABC if it is given: b = 10 cm; c = 20 cm; angle alpha = 60° and the angle beta = 30° (use the Pythagorean theorem and functions sine, cosine, tangent, cotangent)
Sales of products
For 80 pieces of two quality products a total sales is 175 Eur. If the first quality product was sold for n EUR per piece (n natural number) and the second quality product after 2 EUR per piece. How many pieces of the first quality were sold?
Disc
Circumference of the disk is 78.5 cm. What is the circumference of the circular arc of 32° on the disc?

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