Examples for 8th grade - page 46

  1. Buses
    regiojet Buses Ikarus and Karosa simultaneously started at 11:00 from the final station. Ikarus is returned to the station after 30 minutes. Karosa after 45 minutes. At what time both buses again returned to the station?
  2. Rope
    navijak How many meters of rope 10 mm thick will fit on the bobbin diameter of 200 mm and length 350 mm (central mandrel have a diameter 50 mm)?
  3. Pumps
    number-1 First pump flows 16 liters per second into the basin by the second pump 75% of the first and by third pump half more than the second. How long will take fill basin by all three pumps simultaneously volume 15 m3 (cubic meters)?
  4. Distance runner
    vltava_run Distance runner already climbed three fifths of the total route. Thus passed 90 km. How many km he have to stop? How long is his route?
  5. Two numbers
    numbers_1 Find two numbers whose difference and ratio is 10.
  6. Crowns
    money_4 1180 crowns is divided into three people that A got 20% less than B and C by 15% more than B. How many got A,B and C?
  7. Water
    rain In the garden with an area of 8 ares rain 40hl of water. To what heights leveled water?
  8. Rhombus
    rhombus_5 ABCD is a rhombus, ABD is an equilateral triangle and AC is equal to 4. Find the area of the rhombus.
  9. Right triangle - leg
    pythag_triangle Calculate to the nearest tenth cm length of leg in right-angled triangle with hypotenuse length 9 cm and 7 cm long leg.
  10. Pine
    trees How much of a mixed forest rangers want to cut down, if their head said: "We only cut down pine trees, which in our mixed forest 96%. After cut pine trees constitute 91% of all trees left."
  11. Circle inscribed
    inscribed345 Calculate the perimeter and area of a circle inscribed in a triangle measuring 3 , 4 and 5 cm.
  12. Quadrant
    quadrants In what quadrant is a 1501° angle?
  13. Otto and Joachim
    monkey_1 Otto and Joachim go through the woods. After some time Otto tire and make 15 minutes stop. Joachim meanwhile continues at 5 km/h. Otto when he set off again, first running speed of 7 km/h, but it keep only 30 sec and 1 minute must continue at 3 km/h. This.
  14. Wheels
    tractor Small tractor wheel with a diameter of 60 cm must be rotated 8 times to overcome some pathway. How many times must turn the big tractor wheel with a radius 60 cm to overcome the same distance?
  15. Two pumps
    nadrz_4 The first pump fills the tank in 24 hours second pump in another 40 hours. For how long will take fill the tank if operate both pumps at the same time?
  16. Nectar
    vcela Nectar collected by bees contains 70% water. From the nectar of the some process produces honey which contains 19% water. How many kg of nectar bees need to collect to make 1 kg of honey?
  17. 9-gon
    9gon Sum of interiol angles of 9-gon is:
  18. Car consumption
    motor The car has consumption 6.9 l/100 km. How much money will it cost ride 6.9 km in long if diesel price is 1.61 USD/l?
  19. Painters
    3_painters One painter could paint a school for 7 days. The second one for 6 days. It was necessary to paint the school in two days. Next painter was invited and all worked together. How long would this painter painted the school itself?
  20. Rectangle - sides 3
    stvorec If in the rectangle ABCD we enlarge the side a by 5 cm and decrease the side b by 2 cm, the rectangle area will be reduced by 5 cm². When we decrease the length of the side a by 4 cm and and at the same time we increase the length of side b by 3 cm we incr

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