# Examples for 7th grade (seventh) - page 41

1. Square - increased perimeter How many times is increased perimeter of the square, where its sides increases by 150%? If the perimeter of square will increase twice, how much% increases the content area of the square?
2. Money borrow Ms. Kate wants to borrow € 2,000. The company A will borrow ten installments of 240 euros and the first two months does not pay anything. Company B it their position in 12 installments of € 210. Which company has the more favorable interest rate for Ms. K
3. Classs mean Class size is 30 students, math was not worse than sign 2. Determine the number of pupils who were sign 1 if the class had a 1.4 sign average.
4. Rope slack Between two streets 20 m away give the lamp, which is in the middle and hanging 60 cm bellow the taut rope. Can be done with 20.5 meters rope?
5. 6-gon Perimeter of regular hexagon is 113. Calculate its circumradius (radius of circumscribed circle).
6. Triangle eq Calculate accurate to hundredths cm height of an equilateral triangle with a side length 12 cm. Calculate also its perimeter and content area.
7. Seven tractors Seven tractor plowed 308 ha field in four days. How many hectares of fields will plowe 9 tractors in 3 days at the same power?
8. Washing machine The price of washing machine was decreased by 21% and then by 55 € due small sales. After two price decreases cost € 343. How much was originally cost?
9. Three friends Peter is eight times older than Rado, Rado is 3 times younger than Joseph. Together they have 120 years. Determine how many are each of them.
10. Draw a trapezoid Draw a trapezoid if given a = 7 cm, b = 4 cm, c = 3.5 cm, diagonal AC = 5cm. Solve as a construction task.
11. Master and apprentice Master painted the roof in 3 hours and apprentice for 4 hours. How many of roof they painted in hour and how many in three quarters of an hour?
12. 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?
13. Class The class has 18 students. Everyone knows inline skating or skateboarding. Inline skating can ride 11 students on a skateboard 10. How many ride on inline skates and on skateboard?
14. Divide money 2 Ben and Dan had the same amount of money at the start. When Ben gave 300 to Dan, the ratio of Ben 's money to Dan's money became 2:3. How much money did each have at first?
15. Chord 3 What is the radius of the circle where the chord is 2/3 of the radius from the center and has a length of 10 cm?
16. Garden pond Concrete garden pond has bottom shape of a semicircle with a diameter 1.7 m and is 79 cm deep. Daddy wants make it surface. How many liters of water is in pond if watel level is 28 cm?
17. Time 16.2 days ..... how many hours is it? Ladder 6.4 meters long is positioned in the well such that its lower end is distanced from the wall of the well 1.2 m. The upper part of the ladder is supported on the upper edge of the well. How high is the well? Three copiers will do the same in an hour k copies. How many copies would be done in an hour by four such copiers? ? Of the girls who attend primary school are 30% blondes and 70% brunette. 81% blondes and 19% brunette has blue eyes. How many girls attending school altogether if 470 girls has blue eyes?