# 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. 6-gon
Perimeter of regular hexagon is 113. Calculate its circumradius (radius of circumscribed circle).
5. 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?
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. 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?
14. 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?
15. 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?
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?