Examples for 9th grade - page 31

  1. Four-digit number
    numbers_1 Find also a four-digit number, which quadrupled written backwards is the same number.
  2. Water
    storm_1 On the lawn which has area 914 m2 rained 3 mm of water. How many liters of water rained?
  3. Trapezoid ABCD
    trapezoid_2 Calculate the perimeter of trapezoid ABCD if we know the side c=15, b=19 which is also a height and side d=20.
  4. Cube 6
    cubes_20 Volume of the cube is 216 cm3, calculate its surface area.
  5. Workman - shift
    favorit_skoda The worker produces 300 components per shift. How many components would be produced in 18 shift, if his performance gradually increased every shift by 3 components?
  6. Tunnels
    Mysky Mice had built an underground house consisting of chambers and tunnels: • each tunnel leading from the chamber to the chamber (none is blind) • from each chamber lead just three tunnels into three distinct chambers, • from each chamber mice can get to any
  7. The body
    body_cubes The body on the figure consists of cubes with an edge length 10 cm. What surface has this body?
  8. SAS triangle
    triangles2 The triangle has two sides long 7 and 19 and included angle 36°. Calculate area of this triangle.
  9. Katy MO
    reporter_saved6 Kate draw triangle ABC. Middle of AB have mark as X and the center of the side AC as Y. On the side BC wants to find the point Z such that the content area of a 4gon AXZY was greatest. What part of the triangle ABC can maximally occupy 4-gon AXZY?
  10. Mother and daughter
    mom_daughter Three years ago mother was three times older than daughter. After nine years she will be only twice old. How old is mother (and daughter)?
  11. Exam average
    vysvedcenie_2 Average of marks that have on the certificates students of 8.A class in mathematics is exactly 2.45. If we did not add 1 and 3 of sutdents Michael and Alena, who arrived a month ago, it would average exactly 2.5. Determine how many students have class 8.
  12. Warehouse cars
    car_6 From the warehouse started truck at speed 40km/h. After 1hour 30mins started from the same place same direction a car at speed 70 km/h. For how long and at what distance from the warehouse overtake a truck?
  13. Spirit
    lieh From 55% and 80% spirit we would like to produce 0.2 kg of 60% spirit. How many of them we must use in a solution?
  14. Cone container
    kuzel_1 Rotary cone-shaped container has a volume 1000 cubic cm and a height 12 cm. Calculate how much metal we need for making this package.
  15. Chess
    sachovnica How many ways can select 4 fields on classic chess board with 64 fields, so that fields don't has the same color?
  16. Work
    dlazba.pg First paver pave pavement for 27 hours. Second for 27 hours. Started first paver and after 4 hours, join the second. How long will they finish pavement?
  17. Gasholder
    gas_holder The gasholder has spherical shape with a diameter 20 m. How many m3 can hold in?
  18. Grandfather
    family_16 The grandfather is three years older than an grandmother. The average age of the grandmother, the grandfather and their seven grandchildren is 28 years. The grandchildren have a total of 105 years. Calculate how old is grandfather.
  19. Bath
    bathroom In the bath is 30 liters of hot water. Then added 36 liters of cold water at temperature of 19 °C decreased temperature of water to 41 °C. What was the initial temperature of the hot water?
  20. Bronze, tin and copper
    zvon Bronze is an alloy of tin and copper. An alloy of 10% tin and 90% copper is Gunmetal. If it contains 20% tin and 80% copper, it is bell metal. How many tons of molten bell metal and how many tons of copper is needed to make 100 tons of Gunmetal?

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