# Examples for 8th grade - page 83

1. Runner 2 Marian run 12 meters in 8 seconds. How far would Marian run for 70 seconds, if still run at the same pace?
2. Friends James and Jaroslav are friends. Together they had 48 toy cars. But if John took 8 cars from Jaroslav, Jaroslav will be have 1.5 times more toy cars than James. How many toy cars had Jaroslav and James?
3. Summer camp Out of the 180 students at a summer camp, 72 signed up for canoeing. Twenty-three students signed up for trekking, and 13 of those students also signed up for canoeing. Use a two-way table to organize the information and answer the following question: A
4. 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.
5. 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.
6. EQ2 Solve quadratic equation: ?
7. 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?
8. 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.
9. 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. Ladder 10 meters long is staying against the wall so that its bottom edge is 6 meters away from the wall. What height reaches ladder?
11. 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.
12. 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
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. Trench The trench is a four-sided prism. The cross section has a trapezoidal shape with basements of 4m and 6m, the length of the trench is 30m. What is the depth of the trench if we dig 60,000 l of soil.
17. 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.
18. Backpack Large backpack cost CZK 1352, little is 35% cheaper. How much we paid for 5 large and 2 small backpacks?
19. 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?
20. 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.

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