Examples for 8th grade - page 19

  1. Construct 1
    thales_right Construct a triangle ABC, a = 7 cm, b = 9 cm with right angle at C, construct the axis of all three sides. Measure the length of side c (and write).
  2. Journey to grandma
    moto_1 Daniel traveled to grandma. He travel 100 km along. Halfway travel by train, one quarter by bus, one tenth by the bicycle and the rest travel by car. How many km travel km by car?
  3. A family
    smetiarske_auto A family of four pays for garbage collection per year 1800 Kč. How many crowns a year the waste company get from the house where lives 93 people?
  4. Four-digit number
    numbers_1 Find also a four-digit number, which quadrupled written backwards is the same number.
  5. Cross-country competition
    spartakiada Cross-country competition was attended by 76% of pupils of class 9.B. Class consis of 16 boys, two of whom did not run and 4 girls did not run. How many girls go to class 9.B?
  6. Workhorses
    work A team of colleagues done the work in 20 days. After adding 2 colleagues from the beginning the work was completed in 15 days. How many members has the colleague team?
  7. Map 2
    world_map_atlas At what scale is made map if the distance 6.8 km corresponds on the map segment 4 cm long?
  8. Diplomas
    diploma Suzanne helped write out diplomas. Issuance its first took 4 minutes, each next 2.4 minutes. How much time it will take to write out n=23 diplomas (including the first), write out this pace?
  9. Height
    equilateral_triangle Calculate height of the equilateral triangle if its perimeter is 54?
  10. 4s pyramid
    pyramid_regular Regular tetrahedral pyramid has a base edge a=6 and collaterally edge length b=15. What is its height?
  11. Chocholate pyramid
    pyramid_choko How many chocolates are in the third shelf when at the 8th shelf are 41 chocolates in any other shelf is 7 chocolates more the previous shelf.
  12. Beer permille
    pivo In the 5 kg of blood of adult human after three 10° beers consumed shortly after another is 6.6 g of the alcohol. How much is it as per mille?
  13. Plums
    plumbs In the bag was to total 193 plums. Igor took 4 plums and Mary took 4/7 from the rest. How many plums remained in the bag?
  14. Wheels
    tractor Small tractor wheel with a diameter of 60 cm must be rotated 8 times to overcome some pathway. How many times must turn the big tractor wheel with a radius 60 cm to overcome the same distance?
  15. Cyclist
    sagan A cyclist is moving at 26 km/h and follow pedestrian who is walking at speed 7 km/h. Walker has an advantage 13 km. How long take cyclist to catch up with him?
  16. Perpendicular
    perpendicular Determine the slope of the line perpendicular to the line p: y = 9x +7.
  17. Cleaners
    clean Milan would clean up the room for 2.5 hours, Eric would take 10 hours. How long they swept the room together?
  18. Tractors
    tractor_2 Six tractors plowing the field for 8 days. After two days, two tractors broke down. How many days were prolonged work in the field?
  19. Trio 2
    decide Decide whether trio of numbers is the side of a right triangle: 26,24,10.
  20. Sheep
    ships Shepherd tending the sheep. Tourists asked him how much they have. The shepherd said, "there are fewer than 500. If I them lined up in 4-row 3 remain. If in 5-row 4 remain. If in 6-row 5 remain. But I can form 7-row." How many sheep have herdsman?

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.