Examples for 9th grade

Number of examples found: 2561

  • Electronics: Resistors in parallel
    resistors_1 From relation for calculating the resistance of parallel combination of resistors: ? Calculate the R, if R1 = 2Ω a R2 = 15Ω
  • Party
    party-informatikov At the party everyone clink with everyone. Together, they clink 406 times. How many people were at the party?
  • Half of halves
    sequence_geo Half of the square we cut off, then half of the rest, etc. Five cuts we made in this way. What part of the content of the original square is the content of the cut part?
  • Prices
    pokladna The price of the product was increased by 35%. How many percents of the new price we have to make it cheaper so that its price is equal to the original price?
  • Employees
    percent_26 There are 1116 people working in three factory halls. In the first one, there are 18% more than the third, and 60 persons more than the second. How many employees work in individual halls?
  • The mast
    geodet_1 The top of the pole we see at an angle of 45°. If we approach the pole by 10 m, we see the top of the pole at an angle of 60°. What is the height of the pole?
  • Tractors
    tractor_5 Two tractors plow the field in 4 hours together. If the first tractor plow half of the field and then the second tractor completed the job, it would take 9 hours. How many hours does the field plow for each tractor separately?
  • The swing
    houpacka To swing the two girls. Aneta weight 45 kg and Simon 35 kg weight. How far should sit Simon from the middle of swing so it is balanced, if we know that Aneta is sitting at distance 1,5m? How far are girls sitting apart?
  • Holidays - on pool
    pool_4 Children's tickets to the swimming pool stands x € for an adult is € 2 more expensive. There was m children in the swimming pool and adults three times less. How many euros make treasurer for pool entry?
  • Cube walls
    krychle_6 Find the volume and surface area of the cube if the area of one wall is 40cm2.
  • Rectangle
    obdlznik The length of the rectangle is 12 cm greater than 3 times its width. What dimensions and area this rectangle has if ts circumference is 104 cm.
  • Two numbers
    third The sum of two numbers is 1. Identify this two numbers if you know that the half of first is equal to the third of second number.
  • Map scale
    garden_5 Garden has on plan on a scale of 1: 150 width 22 cm and length 35 cm. What is the real area of the garden?
  • Resort
    rekreace In a completely crowded resort was 30% from the Czech Republic quarter visitors were from Slovakia and the rest 135 came from Germany. What capacity have resort?
  • The ship
    ship_1 The ship went upstream speed of 20 km/h in relation to water. River flows at speed 10 km/h. After half an hour, he stopped and returned downstream to the starting point. How long it took way back when even if downstream speed of ship is 20 km/h in relatio
  • The cylindrical container
    cylinder_1 The container has a cylindrical shape the base diameter 0.8 meters has a content area of the base is equal to the content area of the shell. How many full liters of water can be poured maximally into the container?
  • Cu wire
    medeny-drat Copper wire has a length l = 980 m and diameter d = 8 mm. Calculate the weight if density of copper is ρ = 8500 kg/m3. Result round to one decimal place.
  • Building
    Taipei_101 How high is the building that throws horizontal shadow 95.4 m long at angle 50°?
  • Percents from percent
    percent_1 How much is 13% of 20% of 500 greater than 8% of 14% of 200?
  • Circle described
    described_circle_right_triangle The radius of the circle described to the right triangle with 6 cm long leg is 5 cm. Calculate the circumference of this triangle.

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

We will send a solution to your e-mail address. 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...