New math problems - page 9

  1. Two cyclists
    compass_1 Two cyclists started from crossing in the same time. One goes to the north speed 20 km/h, the second eastward at speed 26 km/h. What will be the direct distance cycling 30 minutes from the start?
  2. Combinations
    kvadrat_3 If the number of elements increase by 3, it increases the number of combinations of the second class of these elements 5 times. How many are the elements?
  3. Ladder
    rebrik_3 Ladder 10 meters long is staying against the wall so that its bottom edge is 6 meters away from the wall. What height reaches ladder?
  4. Cube
    cubes_14 One cube has edge increased 5 times. How many times will larger its surface area and volume?
  5. Doubling
    exp_5 The message is spreading that each day has doubled the number of people who know about it. All know message for 20 days. How long known it eighth people?
  6. Modulo
    modulo Find x in modulo equation: 47x = 4 (mod 9) Hint - read as: what number 47x divided by 9 (modulo 9) give remainder 4 .
  7. Two friends
    beers Two friends met as a good man perish together for a beer. After recovery the most important topics (politics, women, football ...), one asks: - And how many do you have children? - I have 3 children. - And how many years have? Friend already not want to an
  8. One percent
    led One percent of all the lights in the city are LED, the remaining 99% are conventional. Other types are not there. John counted them honestly but he had counted only conventional. After a good dinner he registered numbers and he have notice that from all t
  9. Cakes Z8-I-5
    cukriky_5 Mom brought 10 cakes of three types: kokosek was less than laskonek and most were caramel cubes. John chose two different kinds of cakes, Stephan did the same and for Margerith leave only the cakes of the same type. How many kokosek, laskonek and caramel c
  10. Two diagonals
    rhombus-diagonals The rhombus has a side length 12 cm and length of one diagonal 21 cm. What is the length of the second diagonal?
  11. Rectangle pool
    basen_5 Determine dimensions of open pool with a square bottom with a capacity 32 m3 to have painted/bricked walls with least amount of material.
  12. Probably member
    math_series Look at the series 2,6,25,96,285, ? What number should come next?
  13. Rainfall
    rain_2 The annual average rainfall in India was in Cherrapunji in the year 1981 26 461 mm. How many hectoliters of water fell on 1 m2? Would fit this amount of water into a cube of three meters?
  14. Minimum of sum
    derive_1 Find a positive number that the sum of the number and its inverted value was minimal.
  15. Cuboid - ratios
    kvader11 The sizes of the edges of the cuboid are in the ratio 2: 3: 5. The smallest wall have area 54 cm2. Calculate the surface area and volume of this cuboid.
  16. Hello adding
    adding_1 Fill letters instead of digits so the indicated sum (equal letters represent equal digits). What number is hidden under the letter J? A A H A H O A H O J -------------------------- 4 3 2 1
  17. Rectangle diagonals
    rectangle_diagonals_1 It is given rectangle with area 24 cm2 a circumference 20 cm. The length of one side is 2 cm larger than length of second side. Calculate the length of the diagonal. Length and width are yet expressed in natural numbers.
  18. Hypotenuse
    RightTriangleMidpoint_1 Calculate the length of the hypotenuse of a right triangle if the length of one leg is 4 cm and its content area is 16 square centimeters.
  19. Star equation
    numbers_37 Write digits instead of stars so that the sum of the written digits is odd and is true equality: 42 · ∗8 = 2 ∗∗∗
  20. Christmas trees
    vianocny_stromcek Salesman sold Christmas trees: spruce for € 22, pine for € 25 and fir for € 33. At the morning he had the same number of spruce, fir and pine. At the evening he had all the trees entirely sold for € 3,600. How many trees that day salesman sold?

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