# Examples for 8th grade - page 16

- Tanker

An oil tanker can be emptied by the first pump in 4.4 hours. Second pump can empty an tanker in 7.8 hours. If the first pump started at 8:00 and second 1.4 hour later, at what time will the tanker be empty? - Unknown x

If we add to unknown number 72, then divide by 2 and then subtract 29, we get back an unknown number. What is this unknown number? - Perimeter and legs

Determine the perimeter of a right triangle if the length of one leg is 75% length of the second leg and its content area is 24 cm^{2.} - Accidents

The count of accidents in 1993 caused 8009 women which is 7.1%. How many men caused the accidents? - Pentagon

Within a regular pentagon ABCDE point P is such that the triangle is equilateral ABP. How big is the angle BCP? Make a sketch. - Jewel

Rhombus-shaped jewel have area of 86 mm^{2}and the edge in long 10 mm. Calculate the size of rhombus acute angle. - Block

Calculate the volume of a cuboid ABCDEFGH if |AB| = 11 cm, |BC| = 8 cm and the angle ∠CDG = 29.4° - EQL triangle

Calculate inradius and circumradius of equilateral triangle with side a=100 cm. - Parallelogram

Calculate area of the parallelogram ABCD as shown if |AB| = 45 cm, |BC| = 23 cm and angle BAD = 30° - Right triangle

Calculate the missing side b and interior angles, perimeter and area of a right triangle if a=10 cm and hypotenuse c = 16 cm. - Sphere A2V

Surface of the sphere is 306 m^{2.}What is its volume? - Cone and the ratio

Rotational cone has a height 28 cm and the ratio of the base surface to lateral surface is 4: 7. Calculate a surface of the base and the lateral surface. - Wiring

Conduit has a cross section 49^{2}mm. Maybe put it into 5 conductors with a cross section S2 $mm^{2}? - Heron backlaw

Calculate missing side in a triangle with sides 33 and 27 and area 118.3. - Wheat

The rectangle shaped field with dimensions 979 m and 540 m harvested last year was 2775 q wheat. (1 q = 1 quintal = 100 kg). During the year, it was necessary to fix the pipe and therefore did kick wide 6 m parallel to the side of the field 540 m, where no - Steamship

Between the two ports on the river is going steamship. The journey there and back takes 14:49. Downstream steamship traveling at 21 km/h, upstream 9 km/h. What is the distance between the ports? - Triangular pyramid

Calculate the volume and surface area of a regular triangular pyramid whose height is equal to the length of the base edges 10 cm. - Cardboard box

We want to make a cardboard box shaped quadrangular prism with rhombic base. Rhombus has a side of 5 cm and 8 cm one diagonal long. The height of the box to be 12 cm. The box will be open at the top. How many square centimeters cardboard we need, if we cal - Blueberries

Marie earns 1.8 liters of blueberries for 1.2 hours, Peter 2.6 liters for 1.2 hours. How long have earns together one liter? - Leveling

Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 28 m^{2}to the "height" 12 mm if consumtion is 1.7 kg per square meter and millimeter thickness.

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