Examples for 8th grade - page 39
- Slovak broad track
Once upon a time, we learned in school that the Russians have "wider" tracks than our, because they have less tolerable ground. In truth, decide olny area of sleepers, no track gauge. Calculate how many millimeters, our track 1435 mm different from the R
- Hollow sphere
Calculate the weight of a hollow brass sphere (density 8.5 g/cm3), if the outer diameter is 10 cm and wall thickness is 3 mm.
Peter and Stano lawn grass for 3 hours 12 minutes. How long would it take to Peter if Stano lawn grass himself for 384 minutes.
- Football season
Dalibor and Adam together scored 97 goals in the season. Adam scored 9 goals more than Dalibor. How many goals scored each?
We want to prepare 5 kg of sweets for 150 CZK. We will mix cheaper candy: 1 kg for 120 CZK and more expensive candy: 1 kg per 240 CZK. How much of this two types of candy is necessary to prepare this mixture?
- Two numbers
The sum of two numbers is 1. Identify this two numbers if you know that the half of first is equal to the third of second number.
- Vertical prism
The base of vertical prism is a right triangle with leg a = 5 cm and a hypotenuse c = 13 cm. The height of the prism is equal to the circumference of the base. Calculate the surface area and volume of the prism
- Work at plant
Handyman has vowed to do repair work at the plant for 25 days. However, work had to be shortened and therefore gained helper. Together they made all the corrections for 13 1/3 days. How long the work would take helper himself?
- Tetrahedral prism
The height of a regular tetrahedral prism is three times greater than the length of the base edge. Calculate the length of the base edge, if you know that the prism volume is 2187 cm3.
- Cube and water
How many liters of water can fit into a cube with an edge length of 0.11 m?
Loggers wanted to seed more than 700 and less than 800 trees. If they seed in rows of 37, left them 8 trees. If they seed in rows of 43, left the 11 trees. How many trees must seed ?
- Pages of book
Lenka calculated that if every day to read 16 pages of the book, read a book a day earlier than had read only 14 pages a day. How many pages has this book?
- Tetrahedral prism
Calculate surface and volume tetrahedral prism, which has a rhomboid-shaped base, and its dimensions are: a = 12 cm, b = 7 cm, ha = 6 cm and prism height h = 10 cm.
If Alena give Lenka 3 candy will still have 1 more candy. If Lenka give Alena 1 candy Alena will hame twice more than Lenka. How many candies have each of them?
Calculate the perimeter of a regular nonagon (9-gon) inscribed in a circle with a radius 20 cm.
- Supplementary angles
One of the supplementary angles are three times larger than the other. What size is larger of supplementary angles?
- Little hand
What angle shifted little hand on the clock after one hour and 38 minutes?
James paints a fence. If every day instead of 14 planks painted 16 would be done on one day earlier. How many of planks has a fence altogether?
The log has diameter 30 cm. What's largest beam with a rectangular cross-section can carve from it?
- Pool 2
The first supply by the pool fill for five hours and the second fill for six hours, drain should be drained for 15 hours. For how many hours the pool is full, when we open both inlet now and outlet open two hours later?