# Units - examples - page 21

1. Plasticine ball
Plasticine balls have radius r1=85 cm, r2=60 mm, r3=59 cm, r4=86 cm, r5=20 cm, r6=76 mm, r7=81 mm, r8=25 mm, r9=19 mm, r10=14 cm. For these balls.
2. Train from Prague
First train from Prague started at 8:00 hour at 40 kilometers per hour. Train from Ostrava started at 9:20 at 80 km per hour. In how many hours and how far from cities with trains meet if the distance of cities is 400 km.
3. Garden
How many steps of 76 cm circumvent square garden with area 1.8 ha?
4. Hours
How many hours is 9 days?
5. Triangular prism
Calculate the surface area and volume of a triangular prism, base right triangle if a = 3 cm, b = 4 cm, c = 5 cm and height of prism h=12 cm.
6. Two workers
The first worker completed the task by himself in 9 hours, the second in 15 hours. After two hours of joint work left first worker to a doctor and the second finished the job himself. How many hours worked second worker himself?
7. The bridge
Across the circle lakepasses through its center bridge over the lake. At three different locations on the lake shore are three fishermen A, B, C. Which of fishermen see the bridge under the largest angle?
8. Bus driver
The bus driver rides 174 km in the morning, afternoon rides 26 km more. How many kilometers traveled in 5 days if he rides on the same line?
9. Machine
Price of the new machine is € 62000. Every year is depreciated 15% of residual value. What will be the value of the machine after 3 years?
10. Workers
Workers digging a jump pit in the school yard. Pit has a cuboid shape with a length 12 m, a width 20 dm and depth 36 cm. They excavate 0.4 cubic meters of soil an hour. How much time (hours and minutes) is need to the excavate this pit?
11. Balance
The rod are 1.9 m long hanging weights 4 kg and 1 kg on ends. Where are centre of rod (distance from weight 4 kg) to be in balance?
12. Glass mosaic
How many dm2 glass is nessesary to produc 97 slides of a regular 6-gon, whose side has length 21 cm? Assume that cutting glass waste is 10%.
13. Weight of air
What is the weight of air in the living room measuring width 5 m length 2 m and height 2.8 m? Air density is ρ = 1.2 kg/m3.
14. Rectangle A2dim
Calculate the side of the rectangle, if you know that its area is of 2590 m2 and one side is 74 m.
15. Car
Car travels 1/3 of the trip on the first day, second day 2/5 of the trip and left even 340 km for next days. How long is the trip?
16. Thrift woman
Calculate how long grandmother will save to new shoes priced 108 euros if save 3 Eur monthly.
17. Potatoes
Potatoes contain 78.6% starch. How many potatoes need to obtain 27 kg of starch?
18. Map
Forest has an area of ​​36 ha. How much area is occupied by forest on the map at scale 1:500?
19. Triangular prism
Base of perpendicular triangular prism is a right triangle with leg length 5 cm. Content area of the largest side wall of its surface is 130 cm² and the height of the body is 10 cm. Calculate its volume.
20. Grower
Grower harvested 190 kg of apples. Pears harvested 10 times less. a) How many kg pears harvested? b) How many apples and pears harvested? c) How many kg harvested pears less than apples?

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