Ratio - problems

On solving problems and tasks with proportionally we recommend hint rule of three. Rule of three (proportionality) help solve examples of direct and inverse proportionality. Three members makes possible to calculate the fourth - unknown member.
  1. Motion problem
    dragway From Bratislavy to Martina go car at speed 83 km/h. From Martina to Bratislavy go another car at speed 62 km/h. How many minutes before the meeting will be cars 21 km away?
  2. Expansion
    magnification If one side of the rectangle is larger 3-times and second 4-times, what percentage increases the area of rectangle?
  3. VAT
    Tax John paid 1000 Euros in store for purchase. Calculate value added tax (VAT), which paid in purchase, if the VAT rate is 20%.
  4. Rectangle - sides ratio
    rectangle_2 Calculate area of rectangle whose sides are in ratio 1:7 and perimeter is 735.
  5. Ratio
    ratio_1 6 numbers are in the ratio 3:3:4:4:5:5. Their sum is 264. What are the numbers?
  6. Metallurgical enterprise
    iron_industry Metallurgical company daily produces 873 tons of cast iron. How many tons of coke it burns to melt cast iron when 17 tons of cast consumes 13 tons of coke?
  7. Potatoes
    brambory Potatoes contain 78.4% starch. How many potatoes need to obtain 93.7 kg of starch?
  8. Tea blend
    teas Tea blends are maked from two kinds of tea. In standard tea mixture are two teas in the ratio 1:3 and 40 g costs 42 CZK. In the premium tea mixture are weighing two teas in the ratio 1:1 and 50 grams costs 60 CZK. How much cost 10 grams of more expensive k
  9. Temperature calculus
    snowman Calculate percentage of temperature increase if changed from -6 °C to 2 °C?
  10. Linear independence
    colinear_vectors Determine if vectors u=(3; -3) and v=(0; 3) are linear Linear dependent.
  11. Tree trunk
    kmen Calculate the average tree trunk with a circumference of 151 cm.
  12. Map 2
    world_map_atlas At what scale is made map if the distance 6.8 km corresponds on the map segment 4 cm long?
  13. Interest
    MoneyHouse What is the annual interest rate on your account if we put 12700 and after 148 days received 12982.6?
  14. Similarity
    polygons-diagonals The area of the regular 5-gon is 505 cm2. The area of similar 5-gon is 606 dm2. What is the coefficient of similarity.
  15. Painting
    natieranie Jožko with Fero painted the bench for four hours. How many hours would take work if four friends help him?
  16. Apples
    apples_1 Mr. Vesely give to the market his own 48 kg of apples, 40 kg from Mr. Kovar and 72 kg of Mr. Novak. Grossed a total of 1,920 CZK. How must divide income money for apples?
  17. Bottles of juice
    juice_cones How many 2-liter bottles of juice need to buy if you want to transfer juice to 50 pitchers rotary cone shape with a diameter of 24 cm and base side length of 1.5 dm.
  18. Feed for horses
    horses In the kennel have feed for two horses for 21 days. The station brought an additional 5 horses. How many days will last the feed for all the horses if they have the same daily ration?
  19. The classroom
    school In the seventh class the number of boys and girls are at a ratio of 4:5. Boys are 16. How many total students are in the classroom?
  20. Ratios
    circle Divide: a) 250 CZK in the ratio 2:3 b) 1000 CZK in the ratio 4:7:9

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