Examples for 8th grade - page 15

  1. Pedestrian
    pedestrian Pedestrian came started at 7h in the morning with speed 3.6 km/h. At half-past eleven cyclist started at 27 km/h same way. How many minutes take cyclist to catch up pedestrian?
  2. Sea water
    sea_1 Seawater contains about 7% salt. How many dm3 of distilled water we must pour into 14 dm3 of sea water to get water with 1.7% salt?
  3. Two diggers
    two-diggers There are two diggers. One digger digs a pit 83 hours second gidding 1.4 times faster. a) how long took to dig a pit second digger b) how long took dig together
  4. Cable car 2
    lanovka_1 Cable car rises at an angle 39° and connects the upper and lower station with an altitude difference of 345 m. How long is the track of cable car?
  5. Radians
    pi_text Convert 54° to radians. Write result as multiple of number π.
  6. Farmer
    krava The farmer farming 332 ha of arable land and the remaining 11% are meadows and pastures. How much land farmer owns?
  7. Hurry - rush
    bus_3 At an average speed 10 km/h I will come from the school to the bus stop for 29 minutes. How fast I need to go if I need to get to the bus stop in 21 minutes?
  8. OPT
    right_triangle_pythagoras What is the perimerer of a right triangle with the cathetuses 20 cm and 13 cm?
  9. Pizza
    pizza_1 A school survey found that 9 out of 16 students like pizza. If 5 students are chosen at random, what is the probability that all 5 students like pizza?
  10. Cube and water
    krychle_3 How many liters of water can fit into a cube with an edge length of 0.11 m?
  11. Swimming pool 4
    bazen_1 The pool shaped cuboid measuring 12.5 m × 640 cm at the bottom is 960hl water. To what height in meters reaches the water level?
  12. Parachutists
    parasutism Parachutists during freefall firstly held in groups of 4, then of 6, then 9, 12 and finally of 18 members. How many parachutists jump at least should be, if at each group must all be involved.
  13. Sugar - cuboid
    kocky_cukor Pejko received from his master cuboid composed of identical sugar cubes with count between 1000 and 2000. The Pejko eat sugar cubes in layers. The first day eat one layer from the front, second day one layer from right, the third day one layer above. Yet i
  14. BW-BS balls
    balls_3 Adam has a full box of balls that are large or small, black or white. Ratio of large and small balls is 5:3. Within the large balls the ratio of the black to white is 1:2 and between small balls the ratio of the black to white is 1:8 What is the ratio of.
  15. Buses
    regiojet Buses Ikarus and Karosa simultaneously started at 11:00 from the final station. Ikarus is returned to the station after 30 minutes. Karosa after 45 minutes. At what time both buses again returned to the station?
  16. Double percent
    percents What is 70% of 70% of 10500?
  17. Train and car
    car_vs_train The train and the car started at a constant speed to journey. When the train travels 78 km, the car travels 64 km. How many km travels the train when the car travels 78 km?
  18. Reciprocal
    rec_gamma What is the reciprocal of the sum of the reciprocals of 7 and 2?
  19. Expressions
    equation Expression (3a-7).(3a+7) is identical with: ?
  20. Waiting room
    fly In the waiting room are people and flies. Together they have 15 heads and 50 legs (fly has 6 legs). How many people and flies are in the waiting room?

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