Examples for 8th grade - page 52
- Stamps and albums
Michail has in three albums stored 170 stamps. In the first album, there are 14 more than in the second and in the second is by 1/5 less than in the third. How many stamps are in the first album?
Wjat height reach water level in the tray shaped a cuboid, if it is 420 liters of water and bottom dimensions are 120 cm and 70 cm.
Two members will make profit 52 000, - EUR. The forst earned 8% more and the second 10% more and thus earned together 56 700, - EUR. How many will initially each earn?
- High wall
I have a wall 2m high. I need a 15 degree angle (upward) to second wall 4 meters away. How high must the second wall?
- Price reduction
Price of camera is 800 USD on sale its price reduced to 423 USD. Calculate the percentage reduction in the price of the camera.
- Water well
Drilled well has a depth 20 meters and 0.1 meters radius. How many liters of water can fit into the well?
Sisters Zuzka Lenka and Vierka has save for a new bike. Zuzka save € 90, Lenka save € 90 and Vierka save € 82. Missing 30% gave them their mother. What is the price of the bike?
- The ship
The ship went upstream speed of 20 km/h in relation to water. River flows at speed 10 km/h. After half an hour, he stopped and returned downstream to the starting point. How long it took way back when even if downstream speed of ship is 20 km/h in relation
The flowerbed has a length 3500mm and a width 1400mm. How many foil is needed to covers the flowerbed? How many m2 of foil was consumed for its production (add 10% of the material to the joint and waste)? How many liters of air is inside the enclosure? (F
Weight of cargo car is 761 kg. Weight of car is 23% of the total weight of car+cargo. What is the weight of the cargo load?
- Concrete box
The concrete box with walls thick 7 cm has the following external dimensions: length 1.7 m, width 31 cm and height 45 cm. How many liters of soil can fit if I fill it to the brim?
- Areaf of ST
It is given square QHFS with side |HF|=18. Calculate area of triangle QSK if vertex K lie on line FH.
The area of trapezium is 35cm2 find its altitude if the bases are 6cm and 8cm.
- Smallest internal angle
Calculate what size has the smallest internal angle of the triangle if values of angles α:β:γ = 3:4:8
- Alfa, beta, gama
In the triangle ABC is the size of the internal angle BETA 8 degrees larger than the size of the internal angle ALFA and size of the internal angle GAMA is twice the size of the angle BETA. Determine the size of the interior angles of the triangle ABC.
- 5 pumps
Five pump to pump 3 hours 1600 hl of water. How long pumped same amount of water 4 pumps?
How much you will pay CZK for laying tiles in a square room with a diagonal of 8 m if 1 m2 cost CZK 420?
- Middle segment
In a triangle ABC with the side /AB/ = 24 cm is constructed middle segment /DE/ = 18 cm parallel to the side AB at a distance 1 cm from AB. Calculate the height of the triangle ABC to side AB.
- Tangents construct
Circle is given k (S; 2.5 cm) and an outer line p. Construct a tangent t of the circle that has with a line p angle 60°. How many solutions has the task?
- Mr. John
Mr. John wants to buy winter apples Spartan. There are two ways to buy: 1) buy apples at the marketplace, where 1 kg costs 15 CZK. 2) Bring the car to the agricultural farm, where the apples are sold after 9 CZK per kilogram. However, he must pay CZK 150.