# Examples for 9th grade - page 76

1. Truck and car At 6h45min the truck started at a speed of 36 km/h. At 7h30m behind it a passenger car. Find the average speed of passenger car if it will catch truck 72 km away from the factory.
2. Sawmill factory Peter works in the factory. The bus stop is 10 km from the factory. Therefore, always when the bus arrives for Peter, the driver leaves factory and takes him to work. They are coming at the saw exactly at 8:00. Today the bus arrived 11 minutes earlier and.
3. EQ2 Solve quadratic equation: ?
4. Workers Group of workers washing half of the windows of the building in two hours. How long will take half the workers wash all the windows of the building?
5. Outer contact of circles Construct a circle k1 (S1; 1.5 cm), k2 (S2; 2 cm), and K3 (S3; 2.5 cm) so that they are always two outer contact. Calculate the perimeter of the triangle S1S2S3.
6. Parallelogram Side a of parallelogram is twice longer than side b. Its circumference is 78 dm. Calculate the length of the sides of a parallelogram.
7. Six on dice What is the probability that when throwing two dice will fall at least one six?
8. Trees A certain species of tree grows an average of 0.5 cm per week. Write an equation for the sequence that represents the weekly height of this tree in centimeters if the measurements begin when the tree is 200 centimeters tall.
9. Alcohol How many cubic centimeters of 96% alcohol is needed to obtain 0.75 liter of 40% alcohol?
10. Three monks Three medieval monks has task to copy 600 pages of the Bible. One rewrites in three days 1 page, second in 2 days 3 pages and a third in 4 days 2 sides. Calculate for how many days and what day the monks will have copied whole Bible when they begin Wednesd
11. BTC bubble One of the world's experts in bubbles -- Prof. Robert Shiller, a Yale economist -- said Bitcoin "was an amazing example of a bubble" back in 2014. If you exchange fiat US dollar \$100 to BTC in 2010, now in 2017 have value of 72.9 millions dollars. Find.
12. AP - simple Determine the first nine elements of sequence if a10 = -1 and d = 4
13. Land areas Two land areas is 244 m2. The first parcel is 40 m2 less than twice of the second one. What have acreage of each parcel?
14. Rectangle Find the dimensions of the rectangle, whose perimeter is 108 cm and the length is 25% larger than the width.
15. Unknown number 4 I think number. When I divided its square root by its 1/9, I get a number 1. What number am I thinking?
16. Rectangle The length of the rectangle is 12 cm greater than 3 times its width. What dimensions and area this rectangle has if ts circumference is 104 cm.
17. Sale off Product cost 95 euros before sale off. After sale off cost 74 euros and 10 cents. About what percentage of produt became cheaper?
18. Pyramid The pyramid has a base rectangle with a = 6cm, b = 8cm. The side edges are the same and their length = 12.5 cm. Calculate the surface of the pyramid.
19. The pool The pool has a volume of 40 m3 and the water temperature is 20 °C. How much water at 100 °C should we pour into the pool to increase the water temperature by 5 °C?
20. Distilled water Sea water contains 5% salt. How many distilled water should be pour to 40 kg of sea water so that the salt content is 2%. How many kilograms of 2% of sea water we get?

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