Examples for 8th grade - page 29
- Inscribed triangle
To a circle is inscribed triangle so that the it's vertexes divide circle into 3 arcs. The length of the arcs are in the ratio 2:3:7. Determine the interior angles of a triangle.
800 pennies have the same value as 100 ducats. 100 pennies have the same value as 250 tolars. How many ducats has the same value as 100 tolars?
- Snowman 2
On the medal, which has the shape of a circle with a diameter 17 cm is sketched snowman so that the following requirements are met: 1. snowman is composed of three circles, 2. space over snowman is the same as under it, 3. diameters of all circles express
Determine the side of diamond if its content is S = 500 cm2 and one diagonal u2 = 46 cm.
- Dried apples
How many kilograms of fresh apples id needed to 120 kg of dried apples when from 0.4 tons of fresh apples we get 75 kg of dried apples?
- Disinfecting solution
How much distilled water is necessary to pour into 500 ml of 33% hydrogen peroxide solution to obtain 3% disinfecting solution?
Coffee merchant has coffee robusta and arabica species. 1 kg Robusta worth 450 CZK, Arabica 1 kg is 300 CZK more expensive. Calculate how many kilograms of Robusta and Arabica will need to produce 30 kg of the mixture so that the mixture cost is 490 CZK p
- Probability - tickets
What is the probability that when you have 25 tickets in 5000 that you wins the first (one) prize?
- 3sides prism
The base of vertical prism is an isosceles triangle whose base is 10 cm and the arm is 13 cm long. Prism height is three times the height of base triangle. Calculate the surface area of the prism.
- Tank No 8
Tank is filled by one inlet valve with a flow rate of 12 liters per second in 72 minutes. How long take the tank to fill, if we open half an hour after one more inlet?
- Ski tow
The ski club has 168 pupils and used lift with 60 seats, while students always follow the same sequence in filling seats. How many times while riding a ski lift skier sitting in the same seat as the first run?
- Deposit 3
After a year had Martin on bank account € 1764. What was the interest rate when the initial deposit was € 1581?
61% of pupils at the school to eat in the canteen, 1/61 of students who eat in the canteen eat lunch soup. a) What percentage of pupils who eat in the canteen and eat soup for lunch? b) What percentage of all pupils of school eat lunch soup?
Calculate the square root of these numbers:
- Alcohol 2
Two types of alcohol one 70% and second 61% give 11 liters of 57% alcohol. How many liters of each type are in the mixture?
24-member group of divers carries the air for 11 hours of diving. 4 members of the expedition sick or wasn't came. How many hours is sufficient air to other divers?
- 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?
Mr. Peter build a pool shape of a four-sided prism with rhombus base in the garden. Base edge length is 6 m, distance of the opposite walls of the pool is 5 m. Estimated depth is 193 cm. How many hectoliters of water consume Mr. Peter to fill the pool?
What is the slope of the line defined by the equation -4x -2y = -7 ?
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?