Ratio - examples

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. Three shapes
    three_bodies 1/5 of a circle is shaded. The ratio of area if square to the sum of area of rectangle and that of the circle is 1:2. 60% of the square is shaded and 1/3 of the rectangle is shaded. What is the ratio of the area of circle to that of the rectangle?
  2. Three numbers
    fun3_8 The sum of the three numbers is 287. These numbers are in a ratio of 3: 7: 1/4 Define these numbers
  3. Baker
    pekar The baker makes from 10 kg of flour 12 kg dough. How much flour he need to make a 100 kg dough?
  4. Magic belt
    opasok The magic rectangular belt has the property that whenever its owner wants something, the length of the belt is reduced to 1/2 and the width to 1/3. After three such wishes, the belt had a content area 4 cm2. What was its original length if the original wid
  5. Photo egative
    negativ Negative dimensions are 36mm and 28mm. What will be the photo size in the 21:4 ratio?
  6. Sides od triangle
    podobnost Sides of the triangle ABC has length 4 cm, 5 cm and 7 cm. Construct triangle A'B'C' that are similar to triangle ABC which has a circumference of 12 cm.
  7. Angles ratio
    triangles_16 The internal angles of a triangle are in ratio 1:4:5 What kind of triangle is it?
  8. Chocolate
    cokolada Charlie bought 7 same chocolates for 14 Eur. How many euros he pay for 27 chocolates?
  9. Inflation
    dollar What is better for people (employees)? ?
  10. Cyclist
    cyclist_2 A cyclist passes 88 km in 4 hours. How many kilometers he pass in 8 hours?
  11. Troops
    regiment Route is long 203 km and the first day first regiment went at an average speed 20 km/h and journey back 19 km/h. The second day went second regiment same route at an average speed 18 km/h there and back. Which regiment will take route longer?
  12. Chickens
    chickens 4 chickens give 4 eggs in 4 days. How many eggs can give 8 chickens for 8 days?
  13. School trip
    school_trip School trip cost 340.8 USD for one class (24 students). How much would cost a trip for two classes? (both classes together have 44 students)
  14. Blood
    krv In human body the blood is about 7.7% body weight. How many kilograms of blood is in the human body with weight 96 kg?
  15. Series
    posloupnost_an Andrew wrote this series of numbers: 1,3,7,15, .... n. Which number in the series does not belong? ?
  16. Greenhouses
    sklenik Two workers would make installation of greenhouses for 54 hours. For how many hours does the installation 9 workers?
  17. One sixth
    one_sixth How many sixth are two thirds?
  18. Bureaucracy
    bureaucrat The office was attended by 39 people. 9 of them completed the questionnaire. What is the percentage of all people?
  19. Cats
    cats Two cats caught two mice in two days. How many mouses will catch 6 cats for 6 days?
  20. Beer
    piva After three 10° beers consumed in a short time there are 7.4 g of alcohol in 5 kg adult human blood. How much is it per mille?

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