Reason - examples

  1. Earth's diameter
    om5960-v2 The Earth's diameter on the equator is approximately 12750 km. How long does the Gripen flyover the Earth above the equator at 10 km if it is at an average speed of 1500 km / h?
  2. Sea water
    salt_5 One tonne of sea water contains 25 kg of salt. How many tonnes of sea water need to be evaporated to obtain 1 tonne of salt?
  3. Mr and Mrs
    clocks2_8 Mr. Calda and Mrs. Cald have a total of 139 years. How many years have when we know that Mr. Calda is 9 years older than Mrs. Cald
  4. Midnight
    clocks2_7 How many hours are, if the time that elapsed since 8:00 is 2/5 of the time that will past till midnight?
  5. Driver
    truck_2 The driver of the supply car reckoned that at the average speed of 72 km/h arrives to the warehouse for 1 1/4 hours. After 30 km however unintentionally drove to the gas station and have ten minutes delay. At what average speed would have to go the rest.
  6. Four sides of trapezoid
    lichobeznik-stredni_pricka_3 In the trapezoid ABCD is |AB| = 73.6 mm; |BC| = 57 mm; |CD| = 60 mm; |AD| = 58.6 mm. Calculate the size of its interior angles.
  7. Painting
    basen_7 To paint the pool with dimensions: 2 meters depth, 3m x 4m we bought paint to 50 meters square. How many "paint" will be a waste?
  8. First class
    prvni_jakost The shipment contains 40 items. 36 are first grade, 4 are defective. How many ways can select 5 items, so that it is no more than one defective?
  9. Trucks
    bricks Three lorries droved bricks. One drove n bricks at once, second m less bricks than the first and third 300 bricks more the first lorry. The first lorry went 4 times a day the largest went 3 times a day and the smallest 5 times a day. How many bricks br
  10. Unknown number 23
    cisla_4 Find 2/3 of unknown number, which is two thirds of the 99.
  11. Rope
    navijak How many meters of rope 10 mm thick will fit on the bobbin diameter of 200 mm and length 350 mm (central mandrel have a diameter 50 mm)?
  12. Bicycles
    cyclist_11 You're the owner of the transport 's learning playground. Buy bicycles of two colors but you've got to spend accurately 120000 Kč. Blue bike costs 3600Kč and red bicycle 3200Kč.
  13. Family
    family_14 Mom is 42 years old and her daughters 13 and 19. After how many years will mother as old as her daughter together?
  14. Real estate
    house Residential house has three entrances numbered by odd numbers arithmetic progression. The sum of the two numbers on the corner entrances is 50. Calculate the highest of this three numbers.
  15. Salami
    salama How many ways can we choose 5 pcs of salami, if we have 6 types of salami for 10 pieces and one type for 4 pieces?
  16. MO Z6-6-1
    kruhy_1 Write integers greater than 1 to the blanks in the following figure, so that each darker box was product of the numbers in the neighboring lighter boxes. What number is in the middle box?
  17. Workers
    okno2_1 Group of workers washing half of the windows of the building in two hours. How long will take half the workers wash all the windows of the building?
  18. Garden
    zahon_4 Rectangular garden 31 meters 40 centimeters long and 20m30cm wide adjacent with the shorter side with another (fenced) garden and on one longest side is 1 meter wide gate. How many meters of fence is needed to buy? (Estimate, calculate, verify a test ca
  19. Three cats
    three_cats If three cats eat three mice in three minutes, after which time 140 cats eat 140 mice?
  20. Inflation
    dollar What is better for people (employees)? ?

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.