Examples for 8th grade - page 55
The volume of tetrahedral prism is 2.43 m3. Base of prism is a parallelogram in which a side 2,5dm and height ha = 18cm. Calculate the height of the prism.
- Two cars
From the town A to town B started two cars. The first at 7:00 at average speed 60 km per hour, the second at 10:00 at average speed 100 km per hour. The first car will not stay in B, and on the way back meet the second car at half way from A to B. At what.
How many square tiles with the content 121 cm2 has to be ordered for the paving of the square room with a side length of 2.75 meters?
In the room are four-legged chairs, three-legged stool, and all are sitted with (one) people. I counted all the leg room and there were a total of 39. How many are there chairs, stool and people?
- Internal angles
One internal angle of the triangle JAR is 25 degrees. The difference is the size of the two other is 15°. Identify the size of these angles.
Jožko with Fero painted the bench for four hours. How many hours would take work if four friends help him?
How long distance will travel a large (minute) hand on the clock for 39 minutes, if its length is 33 cm?
I have bevel in the ratio 1:6. What is the angle and how do I calculate it?
- Football season
Throughout the football season gave Adam the 23 goals more than Brano and 16 goals less than Karol. Edo gave the 6 goals more Dušan. Karol gave 5 more than Edo. Brano and Edo gave together 17 goals. How many goals gave each boy and how many goals gave the.
Half a kilogram of pork and three-quarters of a kilogram of beef cost total 6.6 USD. One quarter of a kilogram of beef and 1 kilogram of pork cost 6.3 USD. Determine the price of 1 kg of each type of meat.
- Car consumption
The car has consumption 6.9 l/100 km. How much money will it cost ride 6.9 km in long if diesel price is 1.61 USD/l?
- 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?
Solve the inequation: 5k - (7k - 1)≤ 2/5 . (5-k)-2
- EQL triangle
Calculate inradius and circumradius of equilateral triangle with side a=100 cm.
Flowerbed has the shape of an isosceles obtuse triangle. Arm has a size 6.1 meters and an angle opposite to the base size is 93°. What is the distance from the base to opposite vertex?
- Trapezoid ABCD
Calculate the perimeter of trapezoid ABCD if we know the side c=25, b=16 which is also a height and side d=27.
- Against each other
From two points A, B distant 45 km at the same time started two cars against each other at speeds 81 km/h and 67 km/h. How long does cars meet and what distance passes each of them?
What is the weight of concrete cover (lid) to round shape well with a diameter 1.3 m, if the thickness of the cover is 15 cm? 1 m3 of concrete weighs 2190 kg.
The length of the rectangular hop garden Mr. Smith increased by 20% and its width by 20%. What is the percentage change in area of hop garden?
- Negative percentage
In 2003, the company had a loss of 25600 Euros. Two years later he was already in profit 25200 Eur. Calculate what percentage of the company increased profits in this two years.