# Examples for 7th grade (seventh) - page 29

1. The wall We have to build a cuboid wall with dimensions base 30 cm and 45 cm and height 3.25 meters. Calculate how many we need bricks if we spend 400 pieces of bricks to 1 m3 of wall?
2. Water level How high reaches the water in the cylindrical barell with a diameter of 12 cm if there is a liter of water? Express in cm with an accuracy of 1 decimal place.
3. Water pool Pool with volume 990hl completely filled, if water flows by one tap 8 hours and by second tap 6 hours. First tap give 10hl more than second per hour. How many hl flows in each of them in an hour?
4. Canister Gasoline is stored in a cuboid canister having dimensions 44.5 cm, 30 cm, 16 cm. What is the total weight of a full canister when one cubic meter of gasoline weighs 710 kg and the weight of empty canister is 1.5 kg?
5. Triangle For how many integer values of x can 16, 15 and x be the lengths of the sides of triangle?
6. Diameter What is the inside diameter of the cylinder container and if half a liter of water reaches a height 15 cm?
7. Cuboid - simple Calculate the surface area and volume of a cuboid if a = 8 cm, b = 14 cm and c = 6 cm.
8. Slope RR A line has a rise of 2 and a run of 11. What is the slope?
9. Midpoint of segment Point A has coordinates [-16; 23] and the midpoint of the segment AB is the point [2; 12]. What are the coordinates of point B?
10. Tippler Bottle with cork cost 8.8 Eur. The bottle is 0.8 euros more expensive than cork. How much is a bottle and the cork? Car started at 11:40 at speed 54 km/h from A and to B arrived at 12:20. Determine the distance A and B.
12. Decomposition Make decomposition using prime numbers of number 155. Result write as prime factors (all, even multiple)
13. Lie/do not lie The function is given by the rule f(x) = 8x+16. Determine whether point D[-1; 8] lies on this function. Solve graphically or numerically and give reasons for the your answer. In the square ABCD point P is in the middle of the DC side and point Q in the middle pages AD. If the area of quadrilateral BQPC is 49 cm2, what is the area of ABCD?
15. Right triangle Right triangle ABC with side a = 19 and the area S = 95. Calculate the length of the remaining sides.
16. Tons of coal Coal hopper has a capacity of 285 liters. How many tons is it? The bulk density of coal is 916 kg/m3. Once upon a time, we learned in school that the Russians have "wider" tracks than our, because they have less tolerable ground. In truth, decide olny area of sleepers, no track gauge. Calculate how many millimeters, our track 1435 mm different from the R
18. Rabbits Michael breeding rabbits. His 7 rabbits will eat 98 feed rations for 7 days. How many equal portions of feed should be eat 5 rabbits in 6 days?
19. Czech crowns Small Petra save money. Grandfather give her 10 crowns. Petra asked his older sister let her calculate how much he has saved up. Sister told her that he has less than 30 crowns. If the sum is divided by three left one crown. If the sum is divided by the f
20. Average Average of 7 numbers is 65. What is its sum?

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