Examples for 8th grade - page 39

  1. Mom and daughter
    family_1 Mother is 39 years old. Her daughter is 15 years. For many years will mother be four times older than the daughter?
  2. angles in quadrilateral
    4uhelnik What size have angles in quadrilateral (4-gon) if they are in a ratio of 8: 9: 10: 13?
  3. Truck
    auto In 7 hours started from town Krnov truck at speed 40 km/h. Passenger car started against it in 8 hours 30 minutes from the city of Jihlava at speed 70 km/h. Distance between this two cities is 225 km. At what time and at what distance from Krnov this two.
  4. Salt
    sol 1 t of sea water contains 25 kg of salt. How many tons of seawater must be evaporated to obtain 2 q of salt?
  5. Logs
    tramy The log has diameter 30 cm. What's largest beam with a rectangular cross-section can carve from it?
  6. A three-digit numbers
    clocks_1 Determine the total number of positive three-digit numbers that contain a digit 1.
  7. Mother and daughter 2
    mother_baby The mother is 40 years older than her daughter. How old is the mother if her age is eight thirds age of daughter?
  8. Football league
    football_1 In the 4th football league plays each of the 16 participants with each opponent twice. For every victory gets 3 points, 1 point for a draw, a defeat none. After the competition was team with 56 points and 8 defeats at 6th place. How many times have won?
  9. Vectors
    vectors Vector a has coordinates (7; 16) and vector b has coordinates (15; -7). If the vector c = b - a, what is the magnitude of the vector c?
  10. Tachometer
    tatra-dakar2 Tatra's tachometer shows the initial state 154009 km this morning. Tatra today travel at an average speed of 35 km/h. Determine the function that describes the Tatra's tachometer depending on the time. What is the state of tachometer after 4.8 hours?
  11. n-gon
    x-gon What is the side length of the regular 5-gon inscribed in a circle of radius 11 cm?
  12. Bridge
    bridge_circle The bridge arc has a span 41 m and height 3 m. Calculate the radius of the circle arc of this bridge.
  13. Tank
    barrel_1 In the middle of a cylindrical tank with a bottom diameter 350 cm is standing rod which is 31 cm above the water surface. If we bank rod its end reach surface of the water just by the tank wall. How deep is the tank?
  14. Freedom
    family_life In the city are 2/6 of women married for 4/4 men. What proportion of the townspeople is free (not married)? Express as a decimal number.
  15. Fraction
    polynomial For what x expression ? equals zero?
  16. Felix
    astronaut Calculate how much land saw Felix Baumgartner after jump from 22 km above ground. The radius of the Earth is R = 6378 km.
  17. Raffle
    tombola_tickets In the pool is numbers from 1 to 135. What is the probability that a randomly selected number is not a prime number?
  18. Trees
    jablone Along the road were planted 250 trees of two types. Cherry for 60 CZK apiece and apple 50 CZK apiece. The entire plantation cost 12,800 CZK. How many was cherries and apples?
  19. Cancer
    cancer Of the 80 people 50 people ill cancer. What percentage of people isn't ill?
  20. Football season
    ball_f Dalibor and Adam together scored 97 goals in the season. Adam scored 9 goals more than Dalibor. How many goals scored each?

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