# Examples for 7th grade (seventh)

Grandson with grandpa they counted how many years have together. Their product is 365. How many years is the sum of their years.
2. 22/7 circle
Calculate approximately area of a circle with radius 20 cm. When calculating π use 22/7.
3. Two circles
Two circles with a radius 4 cm and 3 cm have a center distance 0.5cm. How many common points have these circles?
4. Annulus
Two concentric circles form an annulus of width 10 cm. The radius of the smaller circle is 20 cm. Calculate the content area of annulus.
5. Arc
What area of a circle occupied the flowers planted in the arc of a circle with radius 4 m with central angle 45°?
6. Rectangle and circle
The rectangle ABCD has side lengths a = 40 mm and b = 30 mm and is circumscribed by a circle k. Calculate approximately how many cm is circle long.
7. Clocks
What distance will describe the tip of minute hand 6 cm long for 20 minutes when we know the starting position with finally enclose hands each other 120°?
8. Plums
In the bag was to total 136 plums. Igor took 3 plums and Mary took 4/7 from the rest. How many plums remained in the bag?
9. Troops - soldiers
Food stocks will last 20 soldiers of the 4-day training. How many days they could extend training if four soldiers become sick?
10. Pumps 3
Two pumps of the same power fill the garden pool for 10 hours. How many of these pumps would have to use if we want to shorten the filling of the pool to four hours?
11. Building base
Excavation for the building base is 350x600x26000. Calculate its volume in m3.
12. Janitor
Janitor tosses 26 cm layer of snow on the school grounds for 90 minutes. How many friends would have to call for help if snow needs to have bowled for 15 minutes. We assume that at the same time bow all the same amount of snow.
13. Hurry - rush
At an average speed 7 km/h I will come from the school to the bus stop for 30 minutes. How fast I need to go if I need to get to the bus stop in 21 minutes?
14. Floating floor
In the new building is considered a floating floor worker in each room. 30 minutes lay 9 m2 of the floor. How long 3 workers laid the floor in 4 rooms with a total area of 90 m2?
15. The rod
The rod is painted in four colors. 55% of the bar is painted in blue, green 0.2 of rod, 1/8 is brown and the remaining 45 cm of white. How long is rod?
16. Supermarket cashiers
When at the supermarket are opened only 2 cash people waiting in the front approximately 12 minutes. How many will shorten the average waiting time in a front where supermarket open another three cashiers?
17. Concrete pipe
How much will cost cover a 6 m long concrete pipe with an outer radius 1.5 m and inner radius 0.8 meters if 1 m2 paint costs 24 €.
18. Heating plant
Workers dump imported coke at heating plant. On the first day used half of the amount, the second day three quarters the rest and on the third day left 120 tons. How much coke they dump at heating plant?
19. Rape
The agricultural cooperative harvested 525 ares of rape, of which received 5.6 tons of rape seeds. Calculate the yield per hectare of rape.
20. Gloves
I have a box with two hundred pieces of gloves in total, split into ten parcels of twenty pieces, and I sell three parcels. What percent of the total amount I sold?

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