# Grade - examples - page 70

1. Base
Base of building is circle with diameter 25 m. Calculate the circumference of a circular trench witch diameter is 41 cm wider than the diameter of the base.
2. Slope
What is the slope of the line defined by the equation -2x +3y = -1 ?
After 548 hours decreases the activity of a radioactive substance to 1/9 of the initial value. What is the half-life of the substance?
4. Hall
Rectangular hall will have pave by square tiles with a side length 15 cm. The hall has length 18 meters and width 3 m. How many tiles need to buy if 2 percent of the amount is disrupted during the work?
5. Square plate
From a square metal plate with a side long 6dm were cut two identical rectangular openings with dimensions of 2.5 dm and 2 dm. Calculate the remainder of the square plate.
6. Cars
Cars started at 7:00 AM. From point A car run at 40 km per hour, from B car run 70 km per hour. Between A and B is 250 km long road. When and where will meet (measured from point A)?
7. Salary
Mr. Johnson's had monthly salary 955 USD since the beginning of year. From which month his salary was increased by 52 USD, when in year earned 11824 USD (enter as a number from 1 to 12)?
8. BW-BS balls
Adam has a full box of balls that are large or small, black or white. Ratio of large and small balls is 5:3. Within the large balls the ratio of the black to white is 1:2 and between small balls the ratio of the black to white is 1:8 What is the ratio of.
9. Secret number
Determine the secret number n, which reversed decrease by 16.4 if the number increase by 16.4.
10. Parallelogram +ľ
| AB | = 76cm, | BC | = 44cm, angle BAD = 30 °. Find the area of the parallelogram.
11. Cylinder
The cylinder surface is 859 dm2, its height is equal to the radius of the base. Calculate height of this cylinder.
12. Two boxes-cubes
Two boxes cube with edges a=38 cm and b = 81 cm is to be replaced by one cube-shaped box (same overall volume). How long will be its edge?
13. Three numbers
The sum of the three numbers is 287. These numbers are in a ratio of 3: 7: 1/4 Define these numbers
14. Medal
Calculate the approximate weight of the gold Olympics medal, if its diameter is 8 cm and a thickness 6 mm. The density of gold find out in the tables or on the Internet.
15. Popsicles
Francis went to buy ice lollies. If he buy 8 popsicles he missed 4 USD. When he buy 7 popsicles, got back 1 USD. How many USD was a popsicle?
16. Daughters
The man conducting the census asks a woman to age of three daughters. Woman says when multiply the age getnumber 72; if their ages add up, get a number of our house, as you see. The man says: That is not enough to calculate their ages. She says: my oldes
17. Nuts, girl and boys
Milena collected fallen nuts and called a bunch of boys let them share. She took a condition: the first boy takes one nut and tenth of the rest, the second takes 2 nuts and tenth new rest, the third takes 3 nuts and tenth new rest and so on. Thus managed.
18. Acute angles
Sizes of acute angles in the right-angled triangle are in the ratio 1: 3. What is size of the larger of them?
19. Equator
Suppose that tourist went on foot over the Globe equator. How many meters more track made ​​his hat on his head as the shoes on your feet? The radius of the earth is 6378 km and height of the tourist is 1.7 m.
20. Motion 2
At 10 o'clock started from place A car speed at 90 km/h. 20 minutes after started from the place B at speed 60 km/h another car. Distance places A and B is 120 kilometers. What time and where they meet?

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