Ratio + percentages - 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.

  1. Altitude difference
    promile What a climb in per mille of the hill long 4 km and the altitude difference is 6 meters?
  2. Earnings per share
    usd The table below shows the stock price, earnings per share, and dividends per share for three companies for a recent year: Deere &Co. Price $65.70 earnings per share $4.40 Dividends per share $1.16 Google price $528.33 earnings per share $27.72 Dividends
  3. Cake ingredients
    cesto The yeast cake contains milk, yeast, sugar, and flour in a ratio of 20: 4: 1: 15. What percentage of flour is in yeast?
  4. Gasoline-oil ratio
    fuel-pump The manufacturer of a scooter engine recommends a gasoline-oil fuel mixture ratio of 15 to 1. In a particular garage, we can buy pure gasoline and a gasoline-oil mixture, which is 75% gasoline. How much gasoline and how much of the gasoline-oil mix do w
  5. Sphere radius
    SpheresDiff The radius of the sphere we reduce by 1/3 of the original radius. How much percent does the volume and surface of the sphere change?
  6. Six percents
    trojuholnik_9 6% of the base is 21. How much is 28% of this base?
  7. Red diplomas
    test_16 He numbers of students with honors in 2013 and 2014 are in ratio 40:49. How big is the year-on-year percentage increase?
  8. Carrot seed
    mrkva2_1 Carrot seed germination is 85%, weight 1000 carrots seeds are 2.4g. How many seeds are likely to germinate if we sow 8g of seeds?
  9. Pupils
    family_29 There are 32 pupils in the classroom, and girls are two-thirds more than boys. a) How many percents are more girls than boys? Round the result to a whole percentage. b) How many are boys in the class? c) Find the ratio of boys and girls in the class. W
  10. Vinegar mixing
    vinegar_2 We mix 70g water and 50g 8% vinegar. How many percents of the solution of vinegar we produce?
  11. Parking
    cars_27 At a building parking, 245 spaces are for cars, 56 are for vans and the rest are for buses. If 14% of all parking spaces are for buses, how many parking spaces are there in the building? How many spaces are for buses?
  12. Percentage 10
    trenky_1 52 shorts and missed 13. Calculate percentage
  13. Rectangle area
    rectangles_5 The length of a rectangle of x units is increased by 10% and its width of y units is increased by 15%. What is the ratio of the area of the old rectangle to the area if the new rectangle?
  14. Image reduction
    picture2 To say that I am mathematically challenged is a gross understatement! I'm trying to help my friend determine how to calculate percentages of reduction or enlargement for a quilt pattern. She is creating a drawing of a cute picture which will become a pi
  15. 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?
  16. Inscribed sphere
    ball-in-cube How many % of the volume of the cube whose edge is 6 meters long is a volume of a sphere inscribed in that cube?
  17. Lathe
    sustruh Calculate the percentage of waste if the cube with 53 cm long edge is lathed to cylinder with a maximum volume.
  18. Climb in percentage
    12_percent_stupanie The height difference between points A and B is 475 m. Calculate the percentage of route climbing if the horizontal distance places A, B is 7.4 km.
  19. Speedometer
    lotus The speedometer of a car reads 66 km/h. It's accurate to within 4.1% What is the maximum possible error?
  20. Carpenter
    tesari From wooden block carpenter cut off a small cuboid block with half the edge length. How many percent of wood he cut off?

Do you have an interesting mathematical word problem that you can't solve it? Submit math problem, and we can try to solve it.



We will send a solution to your e-mail address. Solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...



Our percentage calculator will help you quickly calculate various typical tasks with percentages. Check out our ratio calculator.