Examples for 8th grade - page 85

  1. Diagonals in diamons/rhombus
    diamonds Rhombus ABCD has side length AB = 4 cm and a length of one diagonal of 6.4 cm. Calculate the length of the other diagonal.
  2. Acid solution
    h2so4 By adding 250 grams of a 96% solution of sulfuric acid to its 3% solution its initial concentration was changed to 25%. How many grams of 3% of the acid were used for dilution?
  3. Unknown number 24
    numbs_6 f we add 20, we get 50% of its triple. What is this unknown number?
  4. Two sisters
    cd_disc Two sisters together have 54 CDs. 6/8 CDs has younger sister and is equal to 3/5 of CDs older sisters. How many CDs has each of the sisters?
  5. Chocolate roll
    chocholate_3 The cube of 5 cm chocolate roll weighs 30 g. How many calories will contain the same chocolate roller of a prism shape with a length of 0.5 m whose cross section is an isosceles trapezoid with bases 25 and 13 cm and legs 10 cm. You know that 100 g of this.
  6. Rhombus OWES
    rhombus_6 OWES is a rhombus given that OW 6cm and one diagonal measures 8cm. Find its area?
  7. Triangular prism
    hranol_5 The perpendicular triangular prism is a right triangle with a 5 cm leg. The content of the largest wall of the prism is 130 cm2 and the body height is 10 cm. Calculate the body volume.
  8. Cube walls
    krychle_6 Find the volume and surface area of the cube if the area of one wall is 40cm2.
  9. Tree shadow 3
    stromy_1 What is the diameter of a tree around which is 3m 9dm 7cm long rope wrapped? How big is its cross-sectional area?
  10. Triangle ABC
    rozbor_triangle Construct a triangle ABC is is given c = 60mm hc = 40 mm and b = 48 mm analysis procedure steps construction
  11. Hypotenuse
    RightTriangleMidpoint_1 Calculate the length of the hypotenuse of a right triangle if the length of one leg is 4 cm and its content area is 16 square centimeters.
  12. Empty canister
    kanister_1 The canister is filled with oil weight 17 kg. If filled only half weight 9 kg. What weight does my empty canister have?
  13. Blackberries
    cernice Daniel, Jolana and Stano collected together 34 blackberries. Daniel collected 8 blackberries more than Jolana, Jolana 4 more than Stano. Determine the number blackberries each collected .
  14. Factory and divisions
    factory_2 The factory consists of three auxiliary divisions total 2,406 employees. The second division has 76 employees less than 1st division and 3rd division has 212 employees more than the 2nd. How many employees has each division?
  15. Resistance
    bulb_1 Determine the resistance of the bulb with current 200 mA and is in regular lamp (230V).
  16. Water temperatures
    water2 To 25 liters of water at 50 °C we add 15 liters of water at a different temperature. How many °C should the water be colder than 50 °C so that 40 liters of the water obtained has a temperature 42.5 °C?
  17. Book read
    books_12 If Petra read 10 pages per day, she would read the book two days earlier than she read 6 pages a day. How many pages does a book have?
  18. Spain vs USA
    balls_bw_1 Spain lost to the US by 4 goals. In the match total fell 10 goals. How many goals gave the Spain and how the United States?
  19. Rabbits 3
    rabbits Viju has 40 chickens and rabbits. If in all there are 90 legs. How many rabbits are there with Viju?
  20. Sales off
    lacnejsie shoes cost x euros. First they are discounted by 50%, and then 25% of the new amount. Determine what percentage of the total cost is cheaper.

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.