# Ratio - 7th grade (12y) - 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. Two villages On the map with a scale of 1:40000 are drawn two villages actually 16 km away. What is their distance on the map?
2. Proportion 3 For every 8 mango trees in the orchard, there are 4 star apple trees. If there are 1320 trees, how many trees of each kind are there?
3. Isosceles triangle In an isosceles triangle, the length of the arm and the length of the base are in ration 3 to 5. What is the length of the arm?
4. Sugar production From 1 ton of beet, 150 kg of sugar is produced. To clean 1 ton of sugar 450 kg of lime is consumed. Calculate how many kgs of lime is consumed when processing 1 ton of sugar beet?
5. Kilowatt-hours If the Lewis family used 648 kilowatt-hours of electricity in 12 days, how many kilowatts hours should they use in 24 days at the same rate of usage
6. Ratio of sides 2 The ratio of the side lengths of one square to another is 1:2. Find the ratio of the area of the two squares.
7. In the In the national park, the ratio of the wooded area to grassland is 4: 1. The total area is 385km2. What area is wooded?
8. Three segments The circle is divided into 3 segments. Segment A occupies 1/4 of the area, segment B occupies 1/3 of the area. What part is occupied by section C? In what proportion are areas A: B: C?
9. Donuts Find how many donuts each student will receive if you share 126 donuts in a ratio of 1:5:8
10. Five pumps The water tank is filled with two pumps in 48 minutes. How long would it take to fill it with 5 same pumps?
11. Arble bag A marble bag sold by Rachel's Marble Company contains 5 orange marbles for every 6 green marbles. If a bag has 35 orange marbles, how many green marbles does it contain?
12. Electric energy There are 875 identical light bulbs in the sports hall lighting for 2 hours. How long does the same amount of electricity consume 100 such bulbs?
13. Divide Divide the number 72 in the ratio 7: 2 and calculate the ratio of the numbers found in this order and write down as decimal.
14. Garden The rectangular garden has dimensions of 27 m and 30 m. Peter and Katka split it in a ratio of 4:5. How many square meters did Katkin measure part of the garden?
15. Line segment The 4 cm long line segment is enlarged in the ratio of 5/2. How many centimeters will measure the new line segment?
16. Temperature 5 Temperature outside starts at 0 Fahrenheit. Over time the temperature changes at a rate of -0.6 Fahrenheit per hour. How long will it take for the temperature to reach -4.5 Fahrenheit?
17. Geometric plan At what scale the building plan if one side of the building is 45m long and 12mm long on a plan?
18. Composite ratio Jakub, Aneta, and Lenka divided 1342 USD in the ratio 5/2: 3/10: 1/4. How much did Lenka take?
19. Scale of plan On the plan of the village in the scale of 1: 1000 a rectangular garden is drawn. Its dimensions on the plan are 25mm and 28mm. Determine the area of the garden in ares.
20. Barter There is exchange trade on the market. We know that for two sheepskins we get three goat skins. We also know that for six rabbits skins we get four goat skins. How many rabbit's skins we get for four sheepskins?

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