Examples for 8th grade - page 26

  1. Tank No 8
    tank1 Tank is filled by one inlet valve with a flow rate of 12 liters per second in 72 minutes. How long take the tank to fill, if we open half an hour after one more inlet?
  2. Container
    canister First day got off 1/4 water from full container, second day 1/5 of the remaining water. How many percent remain container filled?
  3. Equation with fractions
    go Solve equation: ? It is equation with fractions.
  4. Alcohol 2
    alko Two types of alcohol one 70% and second 61% give 11 liters of 57% alcohol. How many liters of each type are in the mixture?
  5. Thales
    circles_1 Calculate the length of the Thales' circle described to right triangle with hypotenuse 44 cm.
  6. Bakery
    bread_1 How heavy must prepare bread at a bakery if lose during baking 14% of water and after baking must have 1.6 kg? (Calculate to the nearest gram)
  7. Cuboid
    cuboid_1 The cuboid has a surface area 8710 cm2, the length of its edges are in the ratio 3:2:1. Calculate the volume of the cuboid.
  8. Barrel with liquid
    barrel Barrel with grain weight 263 kg. When it shed 43% of grain, ha weight 170 kg. What is the weight of empty barrel?
  9. Triangle angles
    triangles_2 The angles α, β, γ in triangle ABC are in the ratio 10:5:6. Calculate size of angles.
  10. Apples in baskets
    basket Determine how many apples are in baskets when in the first basket are 4 apples, and in any other is 29 apples more than the previous, and we have eight baskets.
  11. Grass garden
    koseni Mr. Grass would itself be mowed garden for 5 hours. His son Michael could do it for 7 hours. They agreed that they wake up at 5 am and begins to mow together. Ms. Grass needs drive into town at 8.30. Michael says that at that time they're done with work..
  12. Trrops - soldiers
    troops Food stocks will last 20 soldiers of the 4-day training. How many days they could extend training if four soldiers become sick?
  13. Floating floor
    floor In the new building is considered a floating floor worker in each room. 30 minutes lay 9 m2 of the floor. How long 3 workers laid the floor in 4 rooms with a total area of 90 m2?
  14. Father and son
    father_sin Father is three times older than his son. 12 years ago father was nine times older than the son. How old are father and son?
  15. Comparing powers
    diagram How many times is number 55 larger than number 45?
  16. Sawdust
    drevo_kmen_rez How many cubic centimeters of wood sawdust is created by cut the tree trunk with a diameter of 38 cm and when the gap width is 6 mm?
  17. Homework - jumps
    castle_children Sasha jumped 142 cm Peter 4 cm more than Jirka. Jirka 6 cm less than Misha. Misha 7 cm less than Filip and Filip half as much Sasha and Petr together. How far each jumped?
  18. Pool
    bazen Mr. Peter build a pool shape of a four-sided prism with rhombus base in the garden. Base edge length is 6 m, distance of the opposite walls of the pool is 5 m. Estimated depth is 193 cm. How many hectoliters of water consume Mr. Peter to fill the pool?
  19. Work
    dlazba.pg First paver pave pavement for 33 hours. Second for 24 hours. Started first paver and after 5 hours, join the second. How long will they finish pavement?
  20. Vinegar
    vinegar We must dilute 80 liters of 7.6% aqueous vinegar to 4.2% one. How much water is necessary to add?

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