Examples for 8th grade - page 26
The farmer farming 332 ha of arable land and the remaining 11% are meadows and pastures. How much land farmer owns?
- Chemical parison
The blown parison (with shape of a sphere) have a volume 1.3 liters. What is its surface?
Andrew wrote this series of numbers: 1,3,7,15, .... n. Which number in the series does not belong? ?
How many 20-cent coins must be put in a row that next 20-cent coins after them (above) rolled on it axis?
In the box are 6 white, 4 blue and 2 red components. What is the probability that we pull one white, one blue and one red component without returning?
Calculate the sides of the triangle if its area S = 630 and the second cathethus is shorter by 17.
- Trapezoid ABCD v2
Trapezoid ABCD has length of bases in ratio 3:2. The area of riangle ACD is 956 dm2. What is the area of trapezoid ABCD?
- Angles in triangle
The triangle is ratio of the angles α:β = 8:3. Angle γ is 40° greater than α. What are the size of angles of the triangle?
- Three digits number
How many are three-digit integers such that in they no digit repeats?
- Motor physics
Car traveling at 97 km/h on the highway. Pulling power of the motor is 6 kN. Determine engine power in kW.
76% acid was make from same acid of two different concentrations. Amount weaker acid to the stronger acid is in ratio 2:1. What was the concentration of the weaker acid, if stronger had 94% concentration?
Sisters Hanka and Vera goes mostly tograndmother by bicycle. Journey took Hanka 30 minutes and Vera 20 minutes. How long will Vera catch up with Hanka when started from home five minutes later than Hanka?
- Liters in cylinder
Determine the height at which level 20 liters of water in a cylindrical container having a bottom diameter 29 cm.
- Cone in cube
The cube is inscribed cone. Determine the ratio of the volume of cone and cube. The ratio express as a decimal number and as percentage.
The lorry was loaded with 27 boxes of 24 kg. How many boxes with weight 36 kg can be loaded, if total load must be same?
- Trapezoid RT
The plot has a shape of a rectangular trapezium ABCD, where ABIICD with a right angle at the vertex B. side AB has a length 36 m. The lengths of the sides AB and BC are in the ratio 12:7. Lengths of the sides AB and CD are a ratio 3:2. Calculate consumptio
- Family and age ratios
Age of father and son are in the ratio 10:3; age of father and daughter are in the ratio 5:2. How old is father and son, if daughter is 20 years old? In what ratio is age sister and brother?
- Two typists
There are two typists who are rewriting the material 705 pages. First can it handle rewrite yourself for 24 days; the second 12 days. First typist wrote material yourself 4 days rest rewrites yourself second typist. How many days will it take rewriting alt
- Isosceles trapezoid
The lengths of the bases of the isosceles trapezoid are in the ratio 5:3, the arms have a length of 5 cm and height = 4.8 cm. Calculate the circumference and area of a trapezoid.
- Temperature calculus
Calculate percentage of temperature increase if changed from -6 °C to 2 °C?