Examples for 8th grade - page 19

  1. Wiring
    install_pipes Conduit has a cross section 482 mm. Maybe put it into 6 conductors with a cross section S2 $mm2?
  2. 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.
  3. Slope of the pool
    swimming_pool Calculate slope (rise:run) of the bottom of swimming pool long 10 m. Water depth at beginning of pool is 1.16 m (for children) and depth at end is 1.89 m (for swimmers). Slope express as percentage and as angle in degrees.
  4. 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.
  5. 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
  6. Compass
    wind_rose What angle are between directions WSW (WestSouthWest) and SSE (SouthSouthEast) on the compass?
  7. 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?
  8. 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.
  9. 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.
  10. Nine-gon
    9gon_1 Calculate the perimeter of a regular nonagon (9-gon) inscribed in a circle with a radius 13 cm.
  11. Road
    route-66 Average climb of the road is given by ratio 1:15. By what angle road average climb?
  12. Pit
    ihlan_zrezany Pit has shape of a truncated pyramid with rectangular bases and is 3.5 m deep. The length and width of the pit is the top 3 × 1.5 m bottom 1 m × 0.5 m. To paint one square meter of pit we use 0.8 l of green colour. How many liters of paint is needed when w
  13. Lock
    combination-lock Combination lock will open when the right choice of 3 numbers (from 1 to 25 inclusive) is selected. A. How many different lock combinations are possible? B. Is he combination lock named appropriately?
  14. Hexagonal prism
    hexa_prism The base of the prism is a regular hexagon consisting of six triangles with side a = 12 cm and height va = 10.4 cm. The prism height is 5 cm. Calculate the volume and surface of the prism!
  15. 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.
  16. AVG of INT
    seq_moon What is the average of the integers from 9 throuht 52 inclusive?
  17. Elevation
    horizon_diagram What must be the elevation of an observer in order that he may be able to see an object on the earth 782 km away? Assume the earth to be a smooth sphere with radius 6378.1 km.
  18. Height difference
    road What height difference overcome if we pass road 1 km long with a pitch21 per mille?
  19. Lines
    bus Five bus lines runs at intervals 3, 6, 9, 12, 15 minutes. In the morning, suddenly start at 4:00. After how many minutes the bus lines meet again?
  20. Sea
    ship How far can you see from the ship's mast, whose peak is at 14 meters above sea level? (Earth's radius is 6370 km).

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.



To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.