Examples for 8th grade - page 5

  1. Exam average
    vysvedcenie_2 Average of marks that have on the certificates students of 8.A class in mathematics is exactly 2.45. If we did not add 1 and 3 of sutdents Michael and Alena, who arrived a month ago, it would average exactly 2.5. Determine how many students have class 8.
  2. OK circle
    circles2 Calculate the radius (circumradius) of the circle described right triangle with hypotenuse long 17 and one cathetus long 1.
  3. Square diagonal
    square_diagonal Calculate the length of diagonal of the square with side a = 18 cm.
  4. Pool
    swimming-pool The swimming pool is 6 m wide and 14 m long and 185 cm deep. How many hectoliters of water is in it, if the water is 9 cm below its upper edge.
  5. Number ratio
    ratio2 Calculate two positive numbers that its ratio is 4:4 and sum was 184.
  6. Z9-I-4
    numbers_30 Kate thought a five-digit integer. She wrote the sum of this number and its half at the first line to the workbook. On the second line wrote a total of this number and its one fifth. On the third row she wrote a sum of this number and its one nines. Fi
  7. Permill
    permille How many permill is 1931 from 166456?
  8. Invitations
    envelope For every 5 minutes writes Dana 10 invitations, while Anna 14 invitations. How long will write together 120 invitations?
  9. Compare II
    powers Which of the numbers 158, 815 is greater?
  10. Tunnels
    Mysky Mice had built an underground house consisting of chambers and tunnels: • each tunnel leading from the chamber to the chamber (none is blind) • from each chamber lead just three tunnels into three distinct chambers, • from each chamber mice can get to any
  11. Area codes
    us_codes How many 6 digit area codes are possible if the first number can't be zero?
  12. Accidents
    nehoda-pomnik The count of accidents in 1993 caused 8009 women which is 7.1%. How many men caused the accidents?
  13. Ravens
    krkavec The tale of the Seven Ravens were seven brothers, each of whom was born exactly 1.5 years after the previous one. When the eldest of the brothers was 4-times older than the youngest, mother all curse. How old was seven ravens brothers when their mother cur
  14. Madams
    womans During the spring cleaning ladies going to wash windows. Mother takes wash all the windows 5 hours, the grandmother 3 times longer and Paula wash all windows in 5 hours. How many hours will spend washing the windows this "women's team" if working togethe
  15. 2nd class variations
    cards From how many elements you can create 6480 variations of the second class?
  16. ABS
    sphere_nice What is the value of ? ?
  17. Radius
    green_circle Determine the radius of the circle, if its perimeter and area is the same number.
  18. Circle chord
    circleChord What is the length d of the chord circle of diameter 58 mm, if distance from the center circle is 24 mm?
  19. Kites
    drake Boys run kite on a cable of 86 meters long. What is the kite altitude, if the angle from the horizontal plane is 77°?
  20. Acreage
    parcela What acreage has a rectangular plot whose diagonal is 34 meters long and one side has a length of 16 meters. ?

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