Examples for 8th grade - page 68

  1. Ice and water
    ice_playground We want to cover rectangular rink with dimensions of 55 m and 25 m with 4cm thick layer of ice. How many liters of water we need if after freezing water increases its volume by 10%?
  2. Cube 8
    cubes2 The surface of the cube is 0.54 m2. Calculate the length of the cube edge.
  3. Cuboid - edges
    kvadr The sum of all edges cuboid are 8 meters. However, the width is twice shorter than the length and height is seven times longer than the width. Determine the dimensions of the cuboid.
  4. Barbara
    batoh Barborka goes to school with backpack that was 2 - times more expensive than a bag slipper. If backpack was 36 euros cheaper it was cost same as bag slipper. How many cost backpack and how many bas slipper?
  5. Two numbers
    num_3 Determine the numbers x and y so x + y = 8 is truth and the numbers are in the ratio of 4: 5.
  6. 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?
  7. Is equal
    Shazam Is equal following terms? ?
  8. 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?
  9. Five-digit
    cards Find all five-digit numbers that can be created from numbers 12345 so that the numbers are not repeated and then numbers with repeated digits. Give the calculation.
  10. Unions now
    roh The plant has 1,250 employees. The Trade Unions (former ROH, OH) is 18% male, 23% female. Plant management reported that in the trade union is 20% of all employees. How many men and women are in plant and how many are men and women in trade unions?
  11. Average mark
    flag_english Calculate average mark in English, if a student got a couple of 3's, 20% less 2 than 3, and 50% more 1's than the 2's.
  12. Fe vs. H2O
    atoms_Fe The volume of what the body of the same weight is greater - iron or water?
  13. Triangle
    heron1 Determine whether a triangle can be formed with the given side lengths. If so, use Heron's formula to find the area of the triangle. a = 158 b = 185 c = 201
  14. Clock Tower
    clock_3 What angle is betwenn hands on Clock Tower when show 17 hours and 35 minutes?
  15. Radians compare
    28-trigonometry-02 What is greater angle? -0.7 radians or -0.7π radians?
  16. Annulus
    medzikruzie Calculate the area of two circles annulus k1 (S, 3 cm) and k2 (S, 5 cm).
  17. Hexadecimal number
    digitrons What will be hexadecimal number 303 as decimal number?
  18. Pigs
    prasce Pigs are feed by beet.Beet feed containing 12% dry solids, which is 0.72% of digestible crude protein. How much beet must beconsumed in one month (30 days), if the weight of digestible crude protein contained in a daily dose of beet was 0.912 kg?
  19. Rectangle 3-4-5
    diagonal_rectangle_1 The sides of the rectangle are in a ratio of 3:4. The length of the rectangle diagonal is 20 cm. Calculate the content of the rectangle.
  20. Cuboid box
    box How many m2 paper is needed for the sticking cuboid box of dimensions 50 cm, 40 cm and 30 cm? To the folds add one-tenth the area.

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.