Units - examples - page 108

  1. Water lilies
    lekno_2 Water lilies are growing on the pond and their number is doubled every day. The whole layer is covered in 12 days. How many days will it cover 8 layers?
  2. Microorganisms
    microorganisms The first generation of micro-organisms has a population of 13500 members. Each next generation is 11/10 times the previous one. Find out how many generations will reach at least three times members of the first generation.
  3. Mushrooms
    huby_5 Grandfather gathered fresh mushrooms. The fifth was wormwood, and it was thrown away, the other dried up. He obtained 720 grams of dried mushrooms. How many kilograms did the grandfather collect, and by drying the mushrooms they lost 75% of their weight?
  4. Two municipalities
    promile_4 The horizontal distance between municipalities is 39 km. Average sinking is 7 per mille. What is the difference in height between these municipalities?
  5. Bulb
    bulb _2 A 60 W bulb consumes 0.12 kWh of electricity. How long did she stand light without a break?
  6. Pamela
    penize_48 Lara Pamela spends her salary of 3000 for food, clothing, recreation and savings, which are in the ratio of 48:20:15:37, respectively. How much does he spend for savings?
  7. Honza
    calendar_6 Honza is 13 years old and Peter 21 years old. After how many years are their ages will be at ratio 7: 9?
  8. Two ships
    ship_6 The distance from A to B is 300km. At 7 am started from A to B a ferry with speed higher by 20 km/h than a ship that leaves at 8 o'clock from B to A. Both met at 10h 24min. Determine how far they will meet from A and when they reach the destination.
  9. Age
    age_5 In 1960 my age was equal to the digits sum of the year of my birth. What is my age now?
  10. Tailor 5
    textiles_1 A tailor uses 13/4m of cloth to stitch a skirt. How many metres of cloth is needed to stitch 16 skirts?
  11. Apples
    jablka_14 Zuzana bought 3 kg Jonathan apples. Then she noticed that Golden apples were 3 CZK a kilogram cheaper. So they bought 2 kg. For apples, she paid a total of CZK 109. How much did 1 kg Jonathan and how much Golden?
  12. Hour salary
    usd_8 You work for 4 hours on a Saturday and 8 hours on Sunday. You also receive a $50 bonus. You earn $164. How much did you earn per hour?
  13. Dort
    dort_3 The cube-shaped cube box has the dimensions of 30 cm × 30 cm × 12 cm. How many CZK (Czech crowns) would cost be the biggest cake that would fit into the box when a 10 cm³ cake costs CZK 0.5? The cake has the same shape as the box.
  14. Isosceles triangle
    rr_triangle3 The circumference of the isosceles triangle is 32.5 dm. Base length is 153 cm. How long is the leg of this triangle?
  15. Bottles
    flasa_1 The must is sold in 5-liter and 2-liter bottles. Mr Kucera bought a total of 216 liters in 60 bottles. How many liters did Mr. Kucera buy in five-liter bottles?
  16. Temperature increase
    teplomer_19 If the temperature at 9:am is 50 degrees. What is the temperature at 5:00pm if the temperature increases 4 degrees Fahrenheit each hour?
  17. Temperature adding
    teplomer_7 At a weather centre, the temperature at midnight was -2 degree Celsius and by noon it had raised 4 degree Celsius. What is the new temperature?
  18. Ruler and compass
    triangle_bac Use a ruler and compass to construct a triangle ABC with AB 5cm BAC 60° and ACB 45°.
  19. Square to rectangle
    square_rot_2 What is the ratio of the area of a square of side x to the area of a rectangle of a rectangle of width 2 x and length 3
  20. The aquarium
    akvarko_17 The aquarium has a capacity of 18 liters. What is its height when the square bottom is 8 2/3 cm long?

Do you have an 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.