Equation + reason - math problems

  1. Three parallels
    rs_triangle The vertices of an equilateral triangle lie on 3 different parallel lines. The middle line is 5 m and 3 m distant from the end lines. Calculate the height of this triangle.
  2. Students
    skola After the fifth-grade class left 20% of students. In the seventh grade were added 2 pupils, in the eighth 1 pupil, in the ninth, the number has not changed, but it is now tenth students less than it was in the fifth grade. How many pupils are in the 9th.
  3. The tourist
    tourist The tourist traveled 78km in 3 hours. Part of the journey went on foot at 6km/h, the rest of the trip by bus at 30km/h. How long did he walk?
  4. Rectangles
    rectangles_1 Vladimir likes to draw rectangles. Yesterday he created all rectangles that had sides in centimeters and a circumference of 18 cm. How many rectangles of different dimensions have been drawn?
  5. Dividing money
    mince_2 Vilem, Cenek, and Edita divided the money they earned by spreading the leaflet. Vilem got 240 CZK more than Cenek and twice more than Edita. Edita got 400kc less than Vilem.
  6. 1st drug
    pirule First drug pack has an active ingredient ratio of L1: L2 = 2: 1 Second drug pack have a ratio of active ingredients L1: L2 = 1: 3 In which ratio do we have to mix the two packages so that the ratio of substances L1: L2 = 1: 2?
  7. Family
    age The twins Nina and Ema have five years younger brother Michal. Together have 43 years. How old is Michal?
  8. AM of three numbers
    arithmet_seq The number 2010 can be written as the sum of 3 consecutive natural numbers. Determine the arithmetic mean of these numbers.
  9. The devils
    cert The devils weighed in hell with Dorota. They found that Dorota and the two devils weigh 250 kg together and Dorota and the four devils weigh 426 kg. All the devils weigh the same. How Much Does Dorota Weigh?
  10. Land boundary
    rt_triangle The land has the shape of a right triangle. The hypotenuse has a length of 30m. The circumference of the land is 72 meters. What is the length of the remaining sides of the land boundary?
  11. The escalator
    eskalator I run up the escalator at a constant speed in the direction of the stairs and write down the number of steps A we climbed. Then we turn around and run it at the same constant speed in the opposite direction and write down the number of steps B that I climb
  12. Two cities
    cars_30 The car goes from city A to city B at an average speed of 70 km/h, back at an average speed of 50 km/h. If it goes to B and back at an average speed of 60 km/h, the whole ride would take 8 minutes less. What is the distance between cities A and B?
  13. The work
    clock-night-schr_17 The work was to be done by 150 workers. At the beginning of their work, their number reduced by 40, which increased the time of work by 5 and 1/3 of the schedule. How long did work take?
  14. Three painters
    painter_10 One painter would have painted the fence for 15 hours, the second in 12 hours. The plot had to be painted in four hours, so they called the third one, and all worked together. For what time would the third painter paint fence the fence alone?
  15. The King
    gold_4 The King wants to divide his sons equally. He has 42 rubies and 45 diamonds. How many sons and how will they share them?
  16. 45th birthday
    clock-night-schr_1 This year Mrs. Clever celebrated her 45th birthday. Her three children are now 7.11 and 15 years old. In how many years will Mrs. Clever's age be equal to the sum of her children's years?
  17. Harvest time
    clocks2 Grandma and granddaughter Julka reap currants in 15 hours of working together. Julka herself would have currants 10 days after 6 hours of work a day. Find by what percentage the grandma's harvest time was shortened when the granddaughter was involved in c
  18. Before yesterday
    percent He merchant adds a sale sign in his shop window to the showed pair of shoes in the morning: "Today by p% cheaper than yesterday. " After a while, however, he decided that the sign saying: "Today 62.5% cheaper than the day before yesterday". Determine the n
  19. Express train
    trains_13 International express train drove from Kosice to Teplice. In the first 279 km, the track was repaired, and therefore it was moving at a speed of 10km/h less than it was scheduled to drive. The rest of the 465 km trip has increased the speed by 8 km/h than.
  20. Positive integers
    number_line Several positive integers are written on the paper. Michaella only remembered that each number was half the sum of all the other numbers. How many numbers could be written on paper?

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