Equation - 7th grade (12y) - math problems

  1. Cost reduction
    mp3_1 Two MP3 players whose price was equal to originally have been discounted the first by 20%, the second by 35%. After the price reduction was the difference in their prices 750, - CZK. What was the original price of each of the two players?
  2. Working together on project
    work_10 Two employees working on the project. First make it alone for 20 days the second for 24 days. How many days will take to complete project if 5 days they work together then first will take two days holiday and after returning they completes a project toget
  3. Two sisters
    cd_disc Two sisters together have 54 CDs. 6/8 CDs has younger sister and is equal to 3/5 of CDs older sisters. How many CDs has each of the sisters?
  4. Workers
    work_9 9 workers dig a canal 120 meters long for eight hours. For how long would be dig five workers canal 200 meters long?
  5. Way
    ruler_2 If the current way to school was 2 km shorter then if Milan swipe one half he will have already one quarter of the way to school behind. How long is Milan's way to school?
  6. Vehicle tank
    fuel_pump2 A vehicle tank was 3/5 full of petrol. When 21 liters of fuel was added it was 5/6 full. How many liters of petrol can the tank hold?
  7. Family
    family_5 Son is 3/5 smaller than the mother. Mother is 99 cm higher than the son. How tall is the mother?
  8. Mushrooms
    huby_3 Fresh mushrooms contain 90% water, dried only 12%. How many kilograms of fresh mushrooms are needed for 5kg dried?
  9. Classroom
    school_5 One-eighth of 9th class was interested in studying at a grammar school, at a business academy one sixth, at secondary vocational schools quarter, to SOU one third and the remaining three students were interested in the school of art direction. How many st
  10. 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
  11. King's birthday
    ohnostroj To celebrate the king's birthday workers fire 1/5 all purchased rockets. To celebrate the Queen's birthday fire 1/6 of the remaining rockets and to celebrate the birthday of king's son remaining 15,000 rockets. How many rockets they purchased?
  12. Raw meat
    vahy_2 In the school cafeteria for one lunch, they prepare 490 servings of 50 g of boiled meat. Meat loses 30% of its weight by cooking. How many kilograms of raw meat must the school canteen prepare for this lunch to cook?
  13. Flowers
    flowers2 The flower has six flowers and each flower has a number. These are the numbers: 20,40,39,28,8,9. What number will be in the middle of the flower so that the numbers come from the flowers when we subtract and add?
  14. Rings groups
    venn 27 pupils attend some group; dance group attends 14 pupils, 21 pupils sporty group and dramatic group 16 pupils. Dance and sporting attend 9 pupils, dance and drama 6 pupil, sporty and dramatic 11 pupils. How many pupils attend all three groups?
  15. Potatoes
    zemiaky_3 Daniela and Michael would jointly dug potatoes for 7.5 hours. But if Daniela was working alone she would take 2.5 hours more as if he were working with Michael. Determine how much for the work done by Michael himself and how much Daniela herself.
  16. Summands
    magic Find two summands of the number 42, so that its product is minimized.
  17. Equation
    fractions Find x: x + 1/2 = 1/3
  18. Cruise liner
    parnik_1 Cruise liner runs along the river between points A and B. The journey downstream takes 40 minutes 1 hour upriver. The flow rate of the river is 3 km/h. What is the speed of cruise liner?
  19. Simple equation
    axes_1 Solve for x: 3(x + 2) = x - 18
  20. Unknown number
    fractions_6 I think the number - its sixth is 3 smaller than its third.

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