Fractions + ratio - math 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 make possible to calculate the fourth - unknown member.

Number of problems found: 146

  • Proportional relationship
    ratios2 The ordered pairs (6,24) and (1, s) represent a proportional relationship. Find the value of s.
  • Two xeroxes
    xerox The performances of the two copiers are in the ratio 3: 4. A machine with higher power will make 7,200 copies in one hour. How many copies will both machines make together in 5 hours?
  • Answers
    test After the history test, Michaella discovered that the ratio of her correct and incorrect answers is 5: 3. How many correct answers did Michaella have in the test, if she had 6 incorrect answers?
  • Gears
    bicycle_gears_2 The front gear on the bike has 32 teeth and the rear, on the wheel, has 12 teeth. How many times does the rear wheel of the bike turns if you turn the right pedal 30 times? What distance will you go if the circumference of the bicycle wheel is 250 cm?
  • Equilateral cone
    kuzel_rs We pour so much water into a container that has the shape of an equilateral cone, the base of which has a radius r = 6 cm, that one-third of the volume of the cone is filled. How high will the water reach if we turn the cone upside down?
  • Coins
    mince_1 The money - coins are minted from the hardest bronze, which contains copper and tin in a ratio of 41: 9. How much copper and tin are in 2kg of bronze money?
  • Final exam
    vysvedcenie At the final exam, the student answers from three areas, which are evaluated in a ratio of 1: 2: 2. What grade will John receive if he answered as follows: 3,1,2.
  • Twice of radius
    gule How many times does the surface of a sphere decrease if we reduce its radius twice?
  • Divide in ratio
    lines_2 Line segment AB 12 cm long divide in a ratio of 5: 3. How long are the individual parts?
  • Ratio
    maliny Alena collected 7.8 kg of blueberries, 2.6 kg of blackberries, and 3.9 kg of cranberries. Express the ratio in the smallest natural numbers in this order.
  • Summands
    numbers_2 We want to split the number 110 into three summands so that the first and the second summand are in the ratio 4: 5, and the third with the first are in ratio 7: 3. Calculate the smallest of the summands.
  • Double ratio
    phones The mobile phone was twice gradually discounted in the ratio of 3: 2 1 half: 5 quarters. How much did it originally cost if the price was CZK 4,200 after a double discount?
  • Five combers
    permutations_3 Five combers harvest 12 rows of strawberries in 4 hours. How many rows of strawberries will two combers harvest in 10 hours?
  • Age of family
    age The age of father and son is in the ratio 10: 3. The age of the father and daughter is in ratio 5: 2. How old are a father and a son if the daughter is 20?
  • Brass
    brass Brass is an alloy of copper and zinc in a ratio of 3: 2. How many grams does a component that required 270 g of copper weigh?
  • Interior angles
    triangles_1 Calculate the interior angles of a triangle that are in the ratio 2: 3: 4.
  • The angles
    trojuholnik The angles in the triangle are in the ratio 12: 15: 9. Find the angles.
  • The angles ratio
    123_triangle The angles in the ABC triangle are in the ratio 1: 2: 3. find the sizes of the angles and determine what kind of a triangle it is.
  • Lookout tower
    marhat Calculate the height of a lookout tower forming a shadow of 36 m if at the same time a column 2.5 m high has a shadow of 1.5 m.
  • Garden exchange
    land The garden has the shape of a rectangular trapezoid, the bases of which have dimensions of 60 m and 30 m and a vertical arm of 40 m. The owner exchanged this garden for a parallelogram, the area of which is 7/9 of the area of a trapezoidal garden. What is

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