Percentages - 8th grade (13y) - examples

  1. Sales off
    sale_6 The price has decreased by 20%. How many percents do I have to raise the new price to be the same as before the cut?
  2. Acid evaporation
    roztoky_12 How many kilograms of water do we have to evaporate from 100 kg of 32% acid to make it 80% concentration?
  3. Screens
    tv2_3 The area of a 25 inch TV screen is 300 inch² the area of a 40 inch TV screen is 768 inch². The area of the smaller screen is what percent of the area of the larger screen?
  4. Pupils
    skola_23 There are 350 girls in the school, and the other 30% of the total number of pupils are boys. How many pupils does the school have?
  5. Trip to a city
    vylet Lin wants to save $75 for a trip to the city. If she has saved $37.50 so far, what percentage of her goal has she saved? What percentage remains?
  6. On a farm
    sheep-500_3 On a farm, there are 90 rabbits, 700 sheep, 300 cattle and 500 pigs. What percentage of the total number of animals are rabbits?
  7. Mushrooms
    hriby Fresh mushrooms contain 88% water, dried 14% water. How many kilograms of fresh mushrooms should be collected to get 3 kg of dried?
  8. Helmet
    Clock0400_7 In nowadays cycling better results could be obtained not only due to rider physical preparation but also thanks to using updated technologies. One of the most important part of rider´s equipment is his or her helmet. While most bikers wear a helmet mainly
  9. Bonus
    moeny Gross wage was 527 EUR including 16% bonus. How many EUR were bonuses?
  10. River
    kongo_river Calculate how many promiles river Dunaj average falls, if on section long 957 km flowing water from 1454 m AMSL to 101 m AMSL.
  11. Server
    p_pro Calculate how many average minutes a year is the web server is unavailable, the availability is 99.99%.
  12. Discount
    pulover Ladies sweater was twice discounted. First by 17%, then by 17% of the new price. Its final price was 70 USD. Determine the original price of sweater.
  13. Rectangle
    diagonal In rectangle with sides 3 and 10 mark the diagonal. What is the probability that a randomly selected point within the rectangle is closer to the diagonal than to any side of the rectangle?
  14. Vinegar 2
    ocet How many percentage of getvinegar solution, if we mix to 2 liters of 5.9% and 2 liters of 3.5% vinegar?
  15. Ace
    ace From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace?
  16. Tanks
    hasici Fire tank has cuboid shape with a rectangular floor measuring 13.7 m × 9.8 m. Water depth is 2.4 m. Water was pumped from the tank into barrels with a capacity of 2.7 hl. How many barrels were used, if the water level in the tank fallen 5 cm? Wr
  17. Alcohol
    no_alcohol How many 55% alcohol we need to pour into 14 liters 75% alcohol to get p3% of the alcohol? How many 65% alcohol we get?
  18. Gutter
    okap How much metal is needed for production 46 pieces of gutter pipes with the diameter 12 cm and length of 4 m? The plate bends add 2% of the material.
  19. Percentages above 100%
    cmelak What is 122% of 185? What is the meaning of percentages above 100%?
  20. Sea water
    sea_1 Seawater contains about 4.3% salt. How many dm3 of distilled water we must pour into 5 dm3 of sea water to get water with 1.8% salt?

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