Examples for 8th grade - page 90

  1. Walnuts
    orechy_2 x walnuts were in the mission. Dano took 1/4 of nuts Michael took 1/8 from the rest and John took 34 nuts. It stayed here 29 nuts. Determine the original number of nuts.
  2. Candies
    bonbons_9 There are red, blue and green candies in bad. Red to green is in 6:11 ratio and blue to red in a 7: 5 ratio. In what proportion are blue to green candies?
  3. Way
    ruler_2 If the current way to school was 2 km shorter then if Milan swipe one half he will have already one quarter of the way to school behind. How long is Milan's way to school?
  4. Two aircraft
    2aircraft From the airport will start simultaneously two planes, which fly tracks are perpendicular to each other. The first flying speed of 680 km/h and the second 840 km/h. Calculate how far the aircraft will fly for half an hour.
  5. Efficiency
    rychlovarna-kanvica What is the power output of kettle 2 kW with efficiency 90%?
  6. Tricolors
    Flag_of_the_Netherlands.svg From the colors - red, blue, green, black and white, create all possible tricolors.
  7. Socks
    sleva_2 One pair of socks worth CZK 27. Set of 3 pairs of these socks are sold with 10% discount. How many we will pay CZK for two offered sets of socks?
  8. Stairway
    schody Stairway has 20 steps. Each step has a length of 22 cm and a height of 15 cm. Calculate the length of the handrail of staircases if on the top and bottom exceeds 10 cm.
  9. Volume increase
    basen_6 How many percent will increase in the pool 50 m, width 15m if the level rises from 1m to 150cm?
  10. Price increase
    sleva A 20 percent price increase meant a 90-crown raise. How many cost a product after?
  11. Cylindrical tank
    valec_7 Cylindrical tank holds 600hl water and is deep 2.5 m. Calculate the diameter of the cylinder.
  12. Working together on project
    work_10 Two employees working on the project. First make it alone for 20 days the second for 24 days. How many days will take to complete project if 5 days they work together then first will take two days holiday and after returning they completes a project toget
  13. A mast
    stoziar_1 A mast 32 meters high was broken by the wind so that its top touches the ground 16 meters from the pole. The still standing part of the mast, the broken part and the ground form a rectangular triangle. At what height was the mast broken?
  14. Regular n-gon
    10gon_polygon In a regular n-angle polygon the internal angle is 144 degrees. Find the number n indicating the number of sides of this polygon.
  15. Plane II
    compass2 A plane flew 50 km on a bearing 63degrees20 and the flew on a bearing 153degrees20 for 140km. Find the distance between the starting point and the ending point
  16. Cube 1-2-3
    cube_shield_1 Calculate the volume and surface area of the cube ABCDEFGH if: a) /AB/ = 4 cm b) perimeter of wall ABCD is 22 cm c) the sum of the lengths of all edges of the cube is 30 cm.
  17. Boys and girls
    childern There are 48 children in the sports club, boys are 10 more than girls. How many girls go to the club?
  18. Cargo
    tractor_lorry Car with cargo weight 7610 kg. Weight of car is 23% of the total weight of car and cargo. How heavy is cargo?
  19. Adam and Ben
    venn_diagram_3_2 When Ben is so many years old to Adam today, Adam will be 23 years old. When Adam was as old as Ben, Ben was two years old. How old is today Ben and Adam?
  20. Schools
    bulb2_2 Three schools are attended by 678 pupils. To the first attend 21 students more and to the third 108 fewer students than to second school. How many students attend the schools?

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