# Examples for 7th grade (seventh) - page 22

- Carbon dioxide

Calculate how many grams of oxygen are in 50 g of carbon dioxide CO_{2}. Relative atomic mass of oxygen is 16 and of carbon is 12. - Squaring the Circle

Calculating side of the square with the same area as the circle of radius 18. - Pool coating

How many pieces of tiles 25 cm × 15 cm need to coat the bottom and side walls of the pool with bottom dimensions 30 m × 5 m, if the pool can fit up to 271500 liters of water? - Raffle

How many raffle tickets must be purchased by Peter in raffle with issued 200 tickets if he wants to be sure win at least 3 price? In the raffle draws 30 prices. - Again saw

From the trunk of the tree we have to a sculpture beam with rectangular cross-section with dimensions 146 mm and 128 mm. What is the trunk smallest diameter? - Forest nursery

In Forest nursery plant one pine to 1.9 m^{2}. Calculate how many plants are planting in area 362 acres. - Square prism

Calculate the volume of a square prism of high 2 dm wherein the base is: rectangle with sides 17 cm and 1.3 dm - Pennies

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? - 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. - Pumps 3

Two pumps of the same power fill the garden pool for 10 hours. How many of these pumps would have to use if we want to shorten the filling of the pool to four hours? - Construct 1

Construct a triangle ABC, a = 7 cm, b = 9 cm with right angle at C, construct the axis of all three sides. Measure the length of side c (and write). - Ladder

8.3 meters long ladder is leaning against the wall of the well, and its lower end is 1.2 meters from this wall. How high from the bottom of a well is the top edge of the ladder? - Clock

What distance will pass end of 8 cm long hour hand for 15 minutes? - Rising price

The book first become more expensive by 5 euros. New price was later increased by 8%. After the second price increase book cost 46 euros. What was the original price of the book? - Water tank 2

Water tank cuboid is 12 meters long and 6.5 meters wide and 1.2 meters high. How many hectoliters are in the tank when it is filled to 81%? - A family

A family of four pays for garbage collection per year 1800 Kč. How many crowns a year the waste company get from the house where lives 93 people? - angles in quadrilateral

What size have angles in quadrilateral (4-gon) if they are in a ratio of 8: 9: 10: 13? - Passenger car

Passenger car travels 1 km for 2.3 minutes, a truck during a 50 seconds long. How much is the speed of the truck less? - Diagonal

Can be a diagonal of diamond twice longer than it side? - Logik game

Letter game Logik is a two player game, which has the following rules: 1. The first player thinks five-letter word in which no letter is not repeated. 2. The second player writes a five-letter word. 3. The first player answers two numbers - the first numbe

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