Examples for 8th grade - page 65

  1. Prism
    hranol_3bokovy_1 Find the volume and surface area of prism with base of an equilateral triangle with side 7 dm long and the body height of 1.5 m.
  2. Heating plant
    coal_1 Workers dump imported coke at heating plant. On the first day used half of the amount, the second day three quarters the rest and on the third day left 120 tons. How much coke they dump at heating plant?
  3. Book
    books_1 Alena read a book at speed 15 pages per day. If she read twice as fast she should read a book four days earlier. How many pages have a book?
  4. Painters 4
    painter_3 One painter will do the job for 12 days. After a 4 1/3 day he comes second to help him and complete work together for 8 days. How long would work the second painter himself?
  5. Cube 5
    cube_4 The surface of the cube is 15.36 dm2. How will change the surface area of this cube if the length of the edges is reduced by 2 cm?
  6. Chord 5
    kruhy It is given circle k / S; 5 cm /. Its chord MN is 3 cm away from the center of the circle . Calculate its length.
  7. Grandmother
    cukriky_3 Grandmother wants to give the candies to grandchildren that when she gives 5 candy everyone 3 missing and when she gives 4 candies 3 is surplus. How many grandchildren has grandmother and how many candies has?
  8. Concrete block
    abc Determine the volume of concrete block whose one edge of the base has a length 3 meters, body diagonal is 13 meters and its height is 12 meters.
  9. Shoes and slippers
    prezuvky Shoes were three times as many as slippers. If shoes were cheaper by 120, it would be twice as expensive as slippers. How much cost shoes and how much slippers?
  10. Drainage channel
    lich The cross section of the drainage channel is an isosceles trapezoid whose bases have a length of 1.80 m, 0.90 m and arm has length 0.60 meters. Calculate the depth of the channel.
  11. Draw a trapezoid
    konstrukter Draw a trapezoid if given a = 7 cm, b = 4 cm, c = 3.5 cm, diagonal AC = 5cm. Solve as a construction task.
  12. Isosceles trapezoid
    lichobeznik_5 Calculate the content of an isosceles trapezoid whose bases are at ratio 5:3, the arm is 6cm long and it is 4cm high.
  13. Percentage and rectangle
    obdelnik2 About what percentage increases perimeter and area of a rectangle if both the sides 12 cm and 10 cm long we increase by 20%?
  14. Rhumbline
    kosodélník Find circumference and area of the rhumbline ABCD if the short side AD of which has a length of 5 cm, and the heel of the height from D leading to the AB side divides the AB side into two sections of 3 cm and 4 cm.
  15. Interst on savings
    ecb_2 The bank offers 1.6% interest. How many euros have to insert at the beginning if we received € 15 on the interest?
  16. Rain
    bowl-water How many mm of water rained the roof space 75 m2 if the empty barrel with a radius of 8 dm and height 1.2 m filled to 75% its capacity? :-)
  17. Railway wagon
    cargo The railway wagon holds 75 m3 load. Wagon can carry a maximum weight of 30 tonnes. What is the maximum density that may have material with which we could fill this whole wagon? b) what amount of peat (density 350 kg/m3) can carry 15 wagons?
  18. Trip
    pomarancovy-dzus On the trip drank 3/10 of pupils tea, 2/5 cola, 1/4 mineral water and remaining 3 juice. How many students were on the trip?
  19. Two friends
    beers Two friends met as a good man perish together for a beer. After recovery the most important topics (politics, women, football ...), one asks: - And how many do you have children? - I have 3 children. - And how many years have? Friend already not want to an
  20. Typing course
    typewriter_1 Before taking a typing course, Seth could type 30 words per minute. By the end of the course, he was able to type 66 words per minute. Find the percent increase.

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