# Examples for 7th grade (seventh) - page 45

1. Wheel
Diameter of motocycle wheel is 52 cm. How many times rotates wheel on roand long 2 km?
2. Tripled square
If you tripled the length of the sides of the square ABCD you increases its content by 200 cm2. How long is the side of the square ABCD?
3. Ethnicity
Share of ethnicity XY is 26%, which is 1/9 more than in the prewar period. What was the share of that ethnicity in the pre-war period?
4. Runners circle
Pepa circles the track in 36 seconds. Kamil in 42 seconds. They started together. How many seconds will meet again at the start?
5. Photo egative
Negative dimensions are 36mm and 28mm. What will be the photo size in the 21:4 ratio?
6. Percent chaining
Calculate 20% from 70% from 80 km
7. Prism
Find the volume and surface area of prism with base of an equilateral triangle with side 7 dm long and the body height of 1.5 m.
8. Three buses
Three public transport buses depart together from the bus station in the morning. The first bus was returning to the station after 18 minutes, the second after 12 minutes and a third after 24 minutes. How long will again together on the station? Result exp
9. Farm2
The farm bred turkeys, geese, hens and chickens. Everything is 400. Turkeys and geese a hen are 150. No hen has more than one chicken, but some hens has no chick. Half of them is also a quarter of the chickens. When the turkey subtracting 15, we get 75. Ho
10. Trams 2
Square passes two lines of tram. One running every nine minutes, a second interval of 15 minutes. Exactly at 12 o'clock arrived two tram lines in the square. How soon should a similar situation arise again?
11. Tiles
How many square tiles with the content 121 cm2 has to be ordered for the paving of the square room with a side length of 2.75 meters?
12. Two rooms
Woman cleans the room in 30 minutes a man in 90 minutes. How long will take they clean two rooms?
13. Coal
If the daily consumption of 1.6 tons of coal, it is sufficient to supply the boiler for 42 days. How long is sufficient to supply when will burn only 1.2 tons of coal a day ?
14. Algebrogram
Solve algebrogram: mama+anna=vari How many solutions are?
15. Mother and daughter
The ratio of years mother and daughter is 5:2. After 7 years the ratio is 2: 1. How many years ago daughter was born?
16. Double percent
What is 80% of 60% of 2800?
17. 7 roses
Peter buys 7 roses. When he pay for it left him 4 euro. If he bought 5 roses left him 40 euros. How many euros had Peter before buying?
18. Sea water
One tonne of sea water contains 25 kg of salt. How many tonnes of sea water need to be evaporated to obtain 1 tonne of salt?
19. Diagonal - simple
Calculate the length of the diagonal of a rectangle with dimensions 5 cm and 12 cm.
20. Trip
On the trip drank 3/10 of pupils tea, 2/5 cola, 1/4 mineral water and remaining 3 juice. How many students were on the trip?

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