Examples for 8th grade - page 61

  1. Passenger car and truck
    2cars From Kutna Hora left at 11:00 clock a truck at 60 km/h. At 12:30 behind him started passenger car at average speed 80 km/h. At what time and how far from Kutna Hora overtake a passenger car truck?
  2. Cube - wall
    cubes_2 V kocke ABCDEFGH je ?. Aký je povrch kocky?
  3. Rectangle - sides 4
    mouse Perimeter of the rectangle is 72 cm. Calculate the length of the sides that are in the ratio 3:5.
  4. Stairway
    schody Stairway has 20 steps. Each step has a length of 22 cm and a height of 15 cm. Calculate the length of the handrail of staircases if on the top and bottom exceeds 10 cm.
  5. Sum 10
    dices11 What is the probability that two dice throw twice in a row will result the sum of 10?
  6. Triangle eq
    rs_triangle_1 Calculate accurate to hundredths cm height of an equilateral triangle with a side length 12 cm. Calculate also its perimeter and content area.
  7. Land areas
    land Two land areas is 244 m2. The first parcel is 40 m2 less than twice of the second one. What have acreage of each parcel?
  8. Tickets
    stadion_1 On the football tournament ticket cost 45 Kc for standing and 120kč for sitting. Sitting spectators was 1/3 more than standing. The organizers collected a total 12 300 Kc. How many seated and standing seats (spectators)?
  9. Pine wood
    dre-borovica From a trunk of pine 6m long and 35 cm in diameter with a carved beam with a cross-section in the shape of a square so that the square had the greatest content area. Calculate the length of the sides of a square. Calculate the volume in cubic meters of lum
  10. Cuboid
    dodecagon The volume of the cuboid is 245 cm3. Each cuboid edge length can be expressed by a integer greater than 1 cm. What is the surface area of the cuboid?
  11. Three numbers
    numbers_9 Find three numbers so that the second number is 4 times greater than the first and the third is lower by 5 than the second number. Their sum is 67.
  12. Aquarium volume
    akvarium_2 The aquarium has a cuboid shape and dimensions a = 0.3 m, b = 0.85 m, c =? , V = ?. What volume has a body, if after dipping into the aquarium water level rises by 28 mm?
  13. Rectangle - desc circle
    obdelnik_kruh Length of the sides of the rectangle are at a ratio 1: 3 . Radius of the circle circumscribed to rectangle is 10 cm. Calculate the rectangle's perimeter.
  14. Lawns
    grass Before a sports hall are two equally large rectangular lawns, each measuring 40 m and 12 m. Maintenance of 10m² lawn cost 45 CZK yearly. On each lawn is circular flowerbed with a diameter 8 meters. How much money is needed each year to take on lawn care?.
  15. String
    provaz Divide the string length 800 cm in ratio 1: 5
  16. Right triangle ABC
    right_triangle_2 Calculate the perimeter and area of a right triangle ABC, if you know the length of legs 4 cm 5.5 cm and 6.8 cm is hypotenuse.
  17. Triangle SSA
    trojuhol Construct a triangle ABC if |AB| = 5cm va = 3cm, CAB = 50 °. It is to create the analysis and construction steps.
  18. Shop stores
    shipping Workers untied fruit to stores. In the first quarter shipments, in the second fifth shipment, in the third two-fifths of the rest and in the fourth 231 kilograms. How many fruits were together?
  19. Bath salts
    salt_1 Bath salt A weighs 900 grams and costs 36,40 CZK. Bath Salts B weighs 1000 grams, but costs 85 CZK. How much is a bath salt A cheaper than B one?
  20. Two boxes-cubes
    3-kostky Two boxes cube with edges a=74 cm and b = 91 cm is to be replaced by one cube-shaped box (same overall volume). How long will be its edge?

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.



To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.