# Examples for 8th grade - page 30

- Crown

Siblings collect a 2-crowns and 5-crowns. Together have 80 coins with a total of value 310 crowns. How many saved two-crowns and how many five-crowns? - The body

The body on the figure consists of cubes with an edge length 10 cm. What surface has this body? - Mother and daughter

Three years ago mother was three times older than daughter. After nine years she will be only twice old. How old is mother (and daughter)? - Triangle

Calculate heights of the triangle ABC if sides of the triangle are a=48, b=81 and c=98. - Map 2

At what scale is made map if the distance 6.8 km corresponds on the map segment 4 cm long? - Cube - wall

V kocke ABCDEFGH je ?. Aký je povrch kocky? - Father and son

Father is three times older than his son. 12 years ago father was nine times older than the son. How old are father and son? - Area 4gon

Calculate area of 4-gon, two and the two sides are equal and parallel with lengths 7, 15, 7 and 15. Inner angles are 45°, 135°,45°, 135°. - Cuboid 5

Calculate the weight of the cuboid with dimensions of 12 cm; 0.8 dm and 100 mm made from spruce wood (ς = 550 kg/m^{3}). - VAT

VAT is a tax which the state artificially betrays goods and services for final consumption. VAT in Slovakia is 20%. Calculate how much percent pay less tax residents of Switzerland, when VAT is only 8%. - The professor's birthday

Professor of mathematics had 36 birthdays. The director congratulated him. The professor asked the director: "And how old are you?" The director replied: "I'm exactly twice as many years than you were when I was old as to you today." How old is the direc - Rising price

The book first become more expensive by 5 euros. New price was later increased by 13%. After the second price increase book cost 47 euros. What was the original price of the book? - Ladder

7.4 meters long ladder is leaning against the wall of the well and its lower end is 1.1 meters from this wall. How high from the bottom of a well is the top edge of the ladder? - Gon functions

Decide which of the numbers (values of trigonometric functions) are positive and which are negative (or zero). Positive mark +1 and negative -1. - Carbon dioxide

Calculate how many grams of oxygen are in 126 g of carbon dioxide CO_{2}. Relative atomic mass of oxygen is 16 and of carbon is 12. - Diamond ABCD

In the diamond ABCD is the diagonal e = 24 cm and size of angle SAB is 28 degrees, where S is the intersection of the diagonals. Calculate the circumference of the diamond. - ISO Triangle V2

Perimeter of RR triangle (isosceles) is 474 m and the base is 48 m longer than the arms. Calculate the area of this triangle. - Password

The voltage station is every day changing the master password, which consists of three letters. Code generation process does not change and is based on the following procedure: The following letters (A) to (I) correspond to different numbers from 1 to 9. I - Building base

Excavation for the building base is 350x600x26000. Calculate its volume in m^{3.} - Compare II

Which of the numbers 15^{8}, 8^{15}is greater?

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