# Examples for 7th grade (seventh) - page 37

1. Complementary angles
Two angles are complementary. If one angle measures 10°, what is the measure of the second angle?
2. Percent
From 99 children who participated in the ski course were 23 excellent skiers, 13 good and 20 average and the rest were beginners. Calculate this data in percentages.
3. Floor
Rectangular floor of living room has a length 5.4 meters and a circumference 17.2 meters. What is its width?
4. Arithmetic average
The arithmetic mean of the five numbers is exactly 8. The sum of these four numbers is 30. What is the fifth number?
5. Extreme temperatures
USA hit extreme heat wave. Calculate percentage of the air temperature change from normal summer temperature 23 °C to 40 °C.
6. Have solution
The sum of four consecutive even numbers is 96. Determine these numbers.
7. Travel by bus
Five girls traveling by bus. Each holds in each hand two baskets. Each basket contains 5 cats. Each cat has 5 kittens. 3 girls getting off the bus and another girl without baskets go on board. The bus control driver. How many legs are in the bus?
8. Pipe
Steel pipe has a length 2.5 meters. About how many decimetres is 1/3 less than 4/8 of this steel pipe?
9. Three men
Alex is half younger than Jan, which is one-third younger than George. The sum of their ages is 48. How are these three men old?
10. Pool
Pool is filled with two water supply. The first supply fill pool for nine hours, the second for six hours. How many hours will take fill the pool when the water flows in through the first supply 3 hours and then we will open a second supply?
11. Concrete tank
How many m3 of concrete is in the tank shape of a cuboid with dimensions of 2000 cm and 5.6 meters and 70 dm, if the concrete takes up 3/7 of the tank?
12. Velocipede
The front wheel of velocipede from year 1880 had a diameter 1.8 m. If the front wheel turned again one then rear wheel 6 times. What was the diameter of the rear wheel?
13. Rope
Peter has a long rope 2 4/5 meter. Martin has a rope 20 cm longer. What distance ropes achieved if the boys link ropes?
14. Average height
In a class are 34 students. The average height of students is 165 cm. What will be the average height of students in the classroom when two pupils tall 176 cm and 170 cm moved from this school/class?
15. Mr. John
Mr. John wants to buy winter apples Spartan. There are two ways to buy: 1) buy apples at the marketplace, where 1 kg costs 15 CZK. 2) Bring the car to the agricultural farm, where the apples are sold after 9 CZK per kilogram. However, he must pay CZK 150.
16. Painting
To paint the pool with dimensions: 2 meters depth, 3m x 4m we bought paint to 50 meters square. How many "paint" will be a waste?
17. Sputnik
The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800 km/h. How long would it take circle the earth round?
18. Welders
Welder do the job for six hours, the second one for 8 hours. How long do the job third welder if all together can do job in 2 hours?
19. Three Titanics
Three steamers sailed from the same port on the same day. The first came back on the third day, fourth 4th day and the third returned sixth day. How many days after leaving the steamers met again in the harbor?
20. The creek
Workers cleaned the creek within 3 days. The first day cleanse one-fifth the length of the creek, the next day 40% of the length of the stream and the third day 8 km length of the creek. How long is a creek?

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