Examples for 9th grade - page 19

  1. Cinema
    cinema Cinema auditorium is built for 1740 people. The first row is planned for 29 seats and each next gradually 2 more. How many rows of seats will have auditorium?
  2. Workers
    jumps Workers digging a jump pit in the school yard. Pit has a cuboid shape with a length 20 m, a width 20 dm and depth 36 cm. They excavate 0.4 cubic meters of soil an hour. How much time (hours and minutes) is need to the excavate this pit?
  3. Triangular prism
    hranol_3sides The base perpendicular triangular prism is a right triangle whose hypotenuse measures 13 cm and one cathetus 2 cm. Height of the prism is equal to 10/7 of the perimeter of the base. Calculate the surface area of prism.
  4. 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?
  5. Two workers
    mame_nizke_mzdy The first worker completed the task by himself in 9 hours, the second in 18 hours. After two hours of joint work left first worker to a doctor and the second finished the job himself. How many hours worked second worker himself?
  6. Tank
    barrel_1 In the middle of a cylindrical tank with a bottom diameter 350 cm is standing rod which is 31 cm above the water surface. If we bank rod its end reach surface of the water just by the tank wall. How deep is the tank?
  7. Event probability
    dices_1 The probability of event G in 9 independent experiments is 0.48. What is the probability that the event G occurs in one experiment (probability is same)?
  8. Hexagonal prism
    hexa_prism The base of the prism is a regular hexagon consisting of six triangles with side a = 12 cm and height va = 10.4 cm. The prism height is 5 cm. Calculate the volume and surface of the prism!
  9. MO circles
    mo Juro built the ABCD square with a 12 cm side. In this square, he scattered a quarter circle that had a center at point B passing through point A and a semicircle l that had a center at the center of the BC side and passed point B. He would still build a ci
  10. Inscribed rectangle
    circle_desc_rectangular The circle area is 184. Determine the area of inscribed rectangle with one side 10 long.
  11. Machine
    machine Price of the new machine is € 56000. Every year is depreciated 16% of residual value. What will be the value of the machine after 5 years?
  12. Root
    sq_root Use law of square roots roots: ?
  13. Circumscribing
    thales Determine the radius of the circumscribed circle to the right triangle with legs 3 cm and 3 cm.
  14. Sales vs profit
    Acer+vs+Apple Apple sells 45 percent less computes than the Acer but the profit from their sales is 1.7 times higher than Acer. How many times are Apple computer more expensive than Acer?
  15. Cuboid
    kvadr Find the cuboid that has the same surface area as the volume.
  16. Euler problem
    euler Someone buys a 720 tolars towels. If it was for the same money of 6 more towels, it would be 6 tolars cheaper each. How many were towels?
  17. Shooter
    terc The probability that a good shooter hits the center of the target circle I is 0.21. The probability that the target hit intercircle is II 0.36. What is the probability that it hits the target circle I or II?
  18. Triangle KLB
    rovnostranny_trojuholnik It is given equilateral triangle ABC. From point L which is the midpoint of the side BC of the triangle it is drwn perpendicular to the side AB. Intersection of perpendicular and the side AB is point K. How many % of the area of the triangle ABC is area o
  19. Felix
    astronaut Calculate how much land saw Felix Baumgartner after jump from 22 km above ground. The radius of the Earth is R = 6378 km.
  20. Dog
    dog_and_man Man goes with a dog on a long walk 18 km from the house. Man is walking at speed 5.3 km/h and a dog that constantly running between house and man at 17.1 km/h. How many kilometers will run the dog when they reach their destination?

Do you have interesting mathematical example 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 e-mail correctly and check whether you don't have a full mailbox.