Examples for 8th grade - page 18

  1. Blueberries
    boruvky Marie earns 3 liters of blueberries for 3.4 hours, Peter 2.4 liters for 2.9 hours. How long have earns together one liter?
  2. Heron backlaw
    heron_math Calculate missing side in a triangle with sides 17 and 34 and area 275.
  3. Wheat
    field_1 The rectangle shaped field with dimensions 889 m and 1336 m harvested last year was 6235 q wheat. (1 q = 1 quintal = 100 kg). During the year, it was necessary to fix the pipe and therefore did kick wide 3 m parallel to the side of the field 1336 m, where.
  4. Water inlets
    pipe Inlet valve with a flow rate of 12 liters per second is filled tank for 72 minutes. How long take to fill full tank if we open one more such valve half an hour after?
  5. XY triangle
    triangle Determine area of triangle given by line 7x+8y-69=0 and coordinate axes x and y.
  6. Christmas Day
    stedryd In leap years was 53 Sundays. On what day of the week fell to Christmas Day?
  7. Coin and die
    die Flip a coin and then roll a six-sided die. How many possible combinations are there?
  8. Shooter
    terc_1 The shooter fired to a target from distance 11 m The individual concentric circle of targets have a radius increments 1 cm (25 points) by 1 point. Shot was shifted by 8'(angle degree minutes). How many points should win his shot?
  9. Wiring
    install_pipes Conduit has a cross section 482 mm. Maybe put it into 6 conductors with a cross section S2 $mm2?
  10. Compass
    wind_rose What angle are between directions WSW (WestSouthWest) and SSE (SouthSouthEast) on the compass?
  11. Pumps
    water_pump Pump that draws water at velocity 3.5 liters per second water from a construction trench take 35 minutes. a) Find out how many minutes the water would run out of the trench pump that draws 7.4 liters of water per second. b) What is the pumping velocity wo
  12. Slope of the pool
    swimming_pool Calculate slope (rise:run) of the bottom of swimming pool long 30 m. Water depth at beginning of pool is 0.85 m (for children) and depth at end is 1.73 m (for swimmers). Slope express as percentage and as angle in degrees.
  13. Divisibility
    dots Determine the smallest integer which divided 11 gives remainder 4 when divided 15 gives remainder 10 and when divided by 19 gives remainder 16.
  14. Spherical segment
    circular_segment_1 Spherical segment with height h=6 has a volume V=134. Calculate the radius of the sphere of which is cut this segment.
  15. Mystery of stereometrie
    Tetrahedron Two regular tetrahedrons have surfaces 88 cm2 and 198 cm2. In what ratio is their volumes? Write as a fraction and as a decimal rounded to 4 decimal places.
  16. Drunk man
    drunk-man Drunkman has 1.6‰ of alcohol in the blood. How many grams of alcohol has in blood, if he have 7 kg of blood?
  17. 3y inflation
    bread Price of the roll rise in the first year by 9%, the second year fell by 5% and in the third year increased by 3%. Calculate the average annual increase in price of the roll.
  18. Nine-gon
    9gon_1 Calculate the perimeter of a regular nonagon (9-gon) inscribed in a circle with a radius 13 cm.
  19. Road
    route-66 Average climb of the road is given by ratio 1:15. By what angle road average climb?
  20. Lid
    drywell What is the weight of concrete cover (lid) to round shape well with a diameter 1.8 m, if the thickness of the cover is 11 cm? 1 m3 of concrete weighs 2190 kg.

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