Examples for 8th grade - page 79

  1. Earth and Sun
    sun_1 Earth is 150 million km away from the Sun, 300,000 km of sunlight travels in 1 second. How long will the light come from the Sun to the Earth?
  2. Hypotenuse
    sqrt Calculate the length of the hypotenuse of a right triangle with a catheti 71 cm and 49 cm long.
  3. Bags
    kufor The first bag has a weight of 18 kg, the second bag is a one-third lighter than the first and the third bag has three times less the weight of all three bags together. Determine their weights.
  4. Cuboid enlargement
    cubes_12 By how many percent increases the volume of cuboid if its every dimension increases by 30%?
  5. Cars 6
    car_15 At 9:00 am two cars started from the same town and traveled at a rate of 35 miles per hour and the other car traveled at a rate of 40 miles per hour. After how many hours will the cars be 30 miles apart?
  6. Working together
    malovka_1 One painter paint the nursery in 10 days, the second in 8 days. How many days will the nursery be painted if they work together?
  7. Water reservoir
    vodojem The reservoir shape of a cylinder having a diameter 8 m and a height 2.8 m. The device indicates that the reservoir contains 800 hectoliters of water. Calculate how much % of volume is used.
  8. Divisible by 5
    175px-5th_MarDiv How many three-digit odd numbers divisible by 5, which are in place ten's number 3?
  9. Scale 3
    cuboid_4 Miriam room is 3.2 meters wide. It is draw by line segment length 6.4 cm on floor plan. In what scale it is plan of the room?
  10. Equation
    serwisy_chemia_01 ?
  11. Angles in ratio
    angles_1 The size of the angles of the triangle are in ratio x: y = 7: 5 and the angle z is 42° lower than the angle y. Find size of the angles x, y, z.
  12. Four friends
    money_10 Four friends shared the money. Vasek got 1/4 of the total amount. Tonda received 1/3 of the rest of the money, Joe got a half from the second residue and Jirka left 80. How much money get together?
  13. Body diagonal
    cubes3_1 Find the cube surface if its body diagonal has a size of 6 cm.
  14. Regular quadrilateral pyramid
    pyramid_3 Find the volume and surface of a regular quadrilateral pyramid if the bottom edge is 45 cm long and the pyramid height is 7 cm.
  15. Reciprocal equation
    img_reci_1 Determine the root of the equation: 9/x-7/x=1
  16. Conva
    konva_1 How many liters of water fit into the shape of a cylinder with a bottom diameter 20 cm and a height 45 cm?
  17. Potatoes 6
    zemiaky_5 The farmer brought potatoes to the market. In the first hour he sold two-fifths of the potatoes brought, in the second hour he sold five-sixth of the remaining potatoes, and in the third hour he had sold the last 40kg of potatoes. How many kg of potatoes d
  18. Garden
    garden_7 The garden has a rectangular shape with lengths of 25 and 40 meters. It has been expanded so that each of its size increased by one fifth. How many square meters increased its acreage?
  19. Masons
    Pat_a_Mat 1 mason casts 30.8 meters square in 8 hours. How long casts 4 masons 178 meters square?
  20. The ladder
    rebrik33_1 The ladder is 10 m long The ladder is 8 m high How many meters is the distant heel from the wall?

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