Examples for 8th grade - page 23

  1. Diofant equation
    diofantos In the set of integers (Z) solve the equation: ? Write result with integer parameter ? (parameter t = ...-2,-1,0,1,2,3... if equation has infinitely many solutions)
  2. Janitor
    snow Janitor tosses 26 cm layer of snow on the school grounds for 90 minutes. How many friends would have to call for help if snow needs to have bowled for 15 minutes. We assume that at the same time bow all the same amount of snow.
  3. 9-gon
    9gon Sum of interiol angles of 9-gon is:
  4. 6-gon
    hexagons Perimeter of regular hexagon is 41. Calculate its circumradius (radius of circumscribed circle).
  5. Pharmacy
    lekarna At the pharmacy are in one container 20% solution in the second 50% solution of disinfectant. They need to prepare 24 L of 36-percent solution. What amount of solution from each container is needed to mix?
  6. Runner 2
    runner2 Marian run 12 meters in 8 seconds. How far would Marian run for 70 seconds, if still run at the same pace?
  7. Distance runner
    vltava_run Distance runner already climbed three fifths of the total route. Thus passed 90 km. How many km he have to stop? How long is his route?
  8. Isosceles trapezoid v3
    rovnobezky_uhly In an isosceles trapezoid ABCD is the size of the angle β = 71° Determine size of angles α, γ and δ.
  9. Chess
    chess How many different ways can initiate a game of chess (first pass)?
  10. Cuboid aquarium
    cuboid Cuboid 25 times 30 cm. How long is third side if cuboid contains 30 liters of water?
  11. Hockey players
    players After we cycle five hockey players sit down. What is the probability that the two best scorers of this crew will sit next to each other?
  12. Price reduction
    camera Price of camera is 800 USD on sale its price reduced to 423 USD. Calculate the percentage reduction in the price of the camera.
  13. Balance
    balance_weight The rod are 1.7 m long hanging weights 2 kg and 12 kg on ends. Where are centre of rod (distance from weight 2 kg) to be in balance?
  14. Pumps A and B
    pump_2 Pump A fill the tank for 12 minutes, pump B for 24 minutes. How long will take to fill the tank if he is only three minutes works A and then both pumps A and B?
  15. Backpack
    batoh_1 Large backpack cost CZK 1352, little is 35% cheaper. How much we paid for 5 large and 2 small backpacks?
  16. Children
    weight_1 Margaret and Zdena weighs the same and Petra 3 kg more. Together weigh 156 kg. How much does they weigh?
  17. Bundle of candies
    bonbons_3 In the store has 168 chocolates, caramel candies 224 and 196 hard candies. How many packages we can do and how many of candies will be in each package?
  18. 7 roses
    roses_1 Peter buys 7 roses. When he pay for it left him 4 euro. If he bought 5 roses left him 40 euros. How many euros had Peter before buying?
  19. Children
    car_game Less than 20 children is played various games on the yard. They can create a pairs, triso and quartets. How many children were in the yard when Annie came to them?
  20. Do you solve this?
    rectangles_4 Determine area S of rectangle and length of its sides if its perimeter is 96 cm.

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