Examples for 8th grade - page 21

  1. Vacation
    dovolenka Smiths paid a deposit for a vacation of two-sevenths of the total price of the vacation. Then paid also € 550. How much cost their vacation?
  2. Pool
    pool If water flows into the pool by two inlets, fill the whole for 9 hours. First inlet filled pool 8 hour longer than second. How long pool is filled with two inlets separately?
  3. Bicycle wheel
    bicycle Bicycle wheel has a diameter of 60 cm. Approximately how many times the wheel rotates at 3.7 km long trip?
  4. Cakes
    cookies_2 Grandmother baked cakes. Half of its was poppy, quarter with plum jam and 16 cheesecakes. How many cakes she baked in total?
  5. Cube 6
    two cubes.GIF Volume of the cube is 216 cm3, calculate its surface area.
  6. Trip
    pomarancovy-dzus On the trip drank 3/10 of pupils tea, 2/5 cola, 1/4 mineral water and remaining 3 juice. How many students were on the trip?
  7. Water tank 2
    tank_1 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 71%?
  8. Water container
    water_1 Container with water weighs 1.48 kg. When we cast 75% of water container of water weight 0.73 kg. How heavy is an empty container?
  9. Trapezium
    trapezium_1 The area of trapezium is 35cm2 find its altitude if the bases are 6cm and 8cm.
  10. Angles ratio
    3angle_1 In a triangle ABC true relationship c is less than b and b is less than a. Internal angles of the triangle are in the ratio 5:4:9. The size of the internal angle beta is:
  11. Chicken and rabbits (classic)
    zajace Grandmother breeding chickens and rabbits. It found that the yard has 22 heads and 66 legs. How many chickens and rabbits breeding in the yard?
  12. Percentage reduction
    sales_percentages Reducing the unknown number by 36% get number 937.3 Determine unknown number.
  13. Midpoint of segment
    midpoint-segment Point A has coordinates [15; 1] and the midpoint of the segment AB is the point [-20; 13]. What are the coordinates of point B?
  14. Kids
    kids How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge?
  15. Distance
    distance Calculate distance between two points Z[7; -9] and U[-10; -8].
  16. River
    river From the observatory 15 m high and 39 m from the river bank, river width appears in the visual angle φ = 22°. Calculate width of the river.
  17. Diofant equation
    diofantos In the set of integers (Z) solve the equation: ? Write result with integer parameter ? (parameter t = ...-2,-1,0,1,2,3... if equation has infinitely many solutions)
  18. Janitor
    snow Janitor tosses 26 cm layer of snow on the school grounds for 90 minutes. How many friends would have to call for help if snow needs to have bowled for 15 minutes. We assume that at the same time bow all the same amount of snow.
  19. Cuboid
    kvadr Find the cuboid that has the same surface area as the volume.
  20. 9-gon
    9gon Sum of interiol angles of 9-gon is:

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