Examples for 8th grade - page 110

  1. Two gears
    gears-3 The two gears fit together. The larger gear has 32 teeth, the smaller has 20 teeth less. How many times does turn a smaller gear if the bigger gear turns three times?
  2. Area to volume
    two_cubes_2 If the surface area of a cube is 486, find its volume.
  3. Girls
    playground_2 The children's competition was attended by 63 girls, which is 30% of all children's participants. How many children attended this competition?
  4. Bricklayer
    tiles2_2 How much do we pay for a bricklayer laying a pavement in a square room with a diagonal of 8 m, if 1 sqm with work will cost for CZK 420?
  5. Isosceles triangle
    iso_tr_1 In an isosceles triangle, the length of the arm and the length of the base are in ration 3 to 5. What is the length of the arm?
  6. Ebay is not free
    usd_7 Be aware of ebay - if you sell something expensive, fee is painful. There are lot of space for classifieds and local exchange away from global ebay. Calculate ebay+paypal fee if you sale 3037 USD laptop. Formula for ebay fee is 0,30 + 10 % of total earning
  7. Coordinates of midpoint
    linear_eq_4 If the midpoint of the segment is (6,3) and the other end is (8,4) what are the coordinate of the other end?
  8. Three brothers
    family_13 The three brothers have a total of 42 years. Jan is five years younger than Peter and Peter is 2 years younger than Michael. How many years has each of them?
  9. Solve 2
    numbers2_47 Solve integer equation: a +b+c =30 a, b, c = can be odd natural number from this set (1,3,5,7,9,11,13,15)
  10. Ditch
    lichob_2_1 Ditch profile is an isosceles trapezoid with bases of length 80m and 60m. The slope of the side wall of the ditch is 80°. Calculate the ditch depth.
  11. Drying herbs
    vaha_18 Herbs lose 75% weight By drying. How many fresh herbs do you have to collect if you want to make 1.5 kg of dried herbs?
  12. T-shirts and hat
    usd_9 5 t-shirts and a hat cost £62.00 2 t-shirts and a hat cost £29.00 How much does a t-shirt cost ? How much does a hat cost ?
  13. The garden
    zahrada_6 The garden has the shape of a rectangular trapezium. The bases have lengths of 27 meters and 36 meters, the trapezoid's height is 12 meters. Calculate how much fence will cost this garden if one meter costs 1.5 €?
  14. Paper box
    prism3s_4 Calculate how much we'll pay for a three-side shaped prism box with a triangular base, and if it measures 12cm and 1.6dm, the hypotenuse measures 200mm. The box is 34cm high. We pay 0,13 € per square meter of paper.
  15. Bucket
    watertank_4 The bucket half filled with water weighs 5.55 kg, the full bucket weighs 9.85 kg. How much does the bucket weigh?
  16. Temperature conversion
    teplomer_12 The normal human body temperature is 98.6 degrees Fahrenheit. What is the temperature in degrees Celcius?
  17. Inquality
    compare_4 Solve inequality: 3x + 6 > 14
  18. Iron density
    pipe1_2 Calculate the weight of a 2 m long rail pipe with an internal diameter of 10 cm and a wall thickness of 3 mm. The iron density is p = 7.8 g/cm3.
  19. No smoke
    no_smoking Tobacco company NO-SMOKE adorned its stand at the cigarette-type trade fair with the cigarette-shaped. The dimensions of which were 20 times the size of a regular cigarette. The regular cigarette contains 0.8 mg of nicotine. How much nicotine would a giant
  20. An oil
    valec2_13 An oil drum is cut in half. One half is used as a water trough. Use the dimensions; length 82cm, width 56cm to estimate the capacity of the water trough in liters.

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