Examples for 8th grade - page 99

  1. Cube surface and volume
    cube_shield_6 Find the surface of the cube with a volume of 27 dm3.
  2. The tank
    pipe2_4 The tank had 9 inflows to be filled in 21 days. After 9 days, 3 trips out. How many days did the remaining 6 tributaries fill the tank?
  3. Tourist
    tourist A tourist walked an average speed of 3.5 km/h route in 6 hours. Calculate how many hours he would have passed at an average speed of 5.5 km/h.
  4. Spending
    usd_5 If spends 25% of my net pay of $922.28 on entertainment. How much money is that?
  5. Right triangle
    rt_A Calculate the length of the remaining two sides and the angles in the rectangular triangle ABC if a = 10 cm, angle alpha = 18°40'.
  6. Four pavers
    tiles2_4 Four pavers would pave the square in 18 days. How many pavers do you need to add to done work in 12 days?
  7. Bricks pyramid
    The_Great_Pyramid How many 50cm x 32cm x 30cm brick needed to built a 272m x 272m x 278m pyramid?
  8. Big cube
    cubes_23 Calculate the surface of the cube, which is composed of 64 small cubes with an edge 1 cm long.
  9. 7 digit number
    numbers2_49 If 3c54d10 is divisible by 330, what is the sum of c and d?
  10. Flowerbed
    flowers_9 Ondra digs the bed in 20 minutes. Cuba in 30 minutes. For how long do they dig together?
  11. Ratio of sides 2
    square_5 The ratio of the side lengths of one square to another is 1:2. Find the ratio of the area of the two squares.
  12. The painter
    painter_12 In order for the painter to get the desired color, he must mix green and yellow in a ratio of 4: 7. If it has 28 l of green color, how many liters of yellow color should he add? How many liters of mixed color does he get?
  13. Body diagonal
    diagonal_1 Calculate the length of the body diagonal of the 6cm cube.
  14. Soldier
    digging_1 An experienced soldier digs a good trench in 30 hours. Two soldiers dug the same trench each 40 hours. How many hours will the ditch dig all three together?
  15. Budget plan
    penize_49 In the construction of the building, the planned budget exceeded 13%, which was 32,500 euros. How many euros cost built the building?
  16. Is right triangle or not
    triangle_rt1_2 If right triangle ABC, have sides a=13, b=11.5, c=22.5. Find area.
  17. Workers
    workers_34 Two workers will construct the stage at the festival in 54 hours. Organizers need to shorten the assembly time by 42 hours. How many workers must the assembly company send?
  18. Cube diagonals
    cube_diagonals The cube has a wall area of 81 cm square. Calculate the length of its edge, wall, and body diagonal.
  19. Shadow
    shadow_1 A meter pole perpendicular to the ground throws a shadow of 40 cm long, the house throws a shadow 6 meters long. What is the height of the house?
  20. Find radius
    numbers_49 Find radius of circle using pythagorean theorem where a=9, b=r, c= 6+r

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