Examples for 9th grade - page 29

  1. Tourist Jirka
    turisti Distance between the points A and B is 13.5 km. Jirka went from point A to point B unknown speed and for an unknown period of time. Back to the point A went slower by 3 km/h which means that went 20 minutes more. How long Jirka took the return journey?
  2. Trapezoid
    hexphitri Area of trapezoid is 135 cm2. Sides a, c and height h are in a ratio 6:4:3. How long are a,c and h? Make calculation...
  3. Bomber
    b52 Bomber flies 10 km at 600 km/h. At what horizontal distance from the target, must pilot drop the bomb to hit the target? Don't care about air resistance and consider the gravitational acceleration g=9.81 m/s2.
  4. Grandson and granddad
    vnuk_dedo Grandson with grandpa they counted how many years have together. Their product is 365. How many years is the sum of their years.
  5. 30-60-90
    30-60-90 The longer leg of a 30°-60°-90° triangle measures 5. What is the length of the shorter leg?
  6. Quadratic equation
    parabola_1 Solve quadratic equation: 2x2-58x+396=0
  7. Two cars
    TwoCars From the town A to town B started two cars. The first at 7:00 at average speed 60 km per hour, the second at 10:00 at average speed 100 km per hour. The first car will not stay in B, and on the way back meet the second car at half way from A to B. At what.
  8. Iron fence
    fe One field of iron fence consists of 20 iron rods with square cross-section of 1.5 cm side and a long 1 meter. How much weight a field if the density of iron is 7800 kg/m3.
  9. Racer
    car_championship The first racer run at a speed 20 m/s and is 750 meters before the finish and ahead 79 meters before second competitor. At what speed must run the second racer to catch first racer at the finish line?
  10. Pyramid
    3d_shapes Cuboid ABCDEFGH has dimensions AB 3 cm, BC 4 cm, CG 5 cm. Calculate the volume and surface area of a triangular pyramid ADEC.
  11. Square
    percent If the length of the sides of the square we decrease by 25% decrease the content area of 28 cm2. Determine the side length of the original square.
  12. Chicken
    sliepka I threw three chicken for a handful of grains and I noticed that it eat in a ratio of 8:7:6 and two of them grabbed 156 grains. How many grains have fought that chicken?
  13. Cuboids in cube
    shapes How many cuboids with dimensions of 6 cm, 8 cm and 12 cm can fit into a cube with side 96 centimeters?
  14. Interest
    dollars Calculate how much you earn for 10 years 43000 deposit if the interest rate is 1.3% and the interest period is a quarter.
  15. Cube and water
    krychle_3 How many liters of water can fit into a cube with an edge length of 0.11 m?
  16. Circle sector
    vysec Circular sector with a central angle 80 ° has area 1257 cm2. Calculate its radius r.
  17. Building
    building The building I focused at an angle 30°. When I moved 5 m building I focused at an angle 45°. What is the height of the building?
  18. Flowerbed 2
    flowerbed Around the square flower bed in a park is sidewalk 2 m wide. The area of ​​this sidewalk is 243 m2. What is the area of the flowerbed?
  19. Divisors
    one Find all divisors of number 493. How many are them?
  20. Cars plates
    car_plate How many different licence plates can country have, given that they use 3 letters followed by 3 digits?

Do you have an interesting mathematical word problem that you can't solve it? Enter it, and we can try to solve it.



To this e-mail address, we will reply solution; solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...