Examples for 8th grade - page 14

  1. TVs
    tv Production of television sets increased from 3,500 units to 4,200 units. Calculate the percentage of production increase.
  2. 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?
  3. Diagonal in rectangle
    q In that rectangle ABCD is the center of BC point E and point F is center of CD. Prove that the lines AE and AF divide diagonal BD into three equal parts.
  4. Conference
    conference 97 is the total number of employees. The conference was attended by 34 employees. How much is it in percent?
  5. 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?
  6. 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?
  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. 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?
  9. Unknown x
    UnknownX If we add to unknown number 72, then divide by 2 and then subtract 29, we get back an unknown number. What is this unknown number?
  10. Square
    1square Calculate area of the square with diagonal 70 cm.
  11. Chess
    sachovnica How many ways can select 3 fields on classic chess board with 64 fields, so that fields don't has the same color?
  12. Cleaners
    clean Milan would clean up the room for 2.5 hours, Eric would take 10 hours. How long they swept the room together?
  13. Gasholder
    gas_holder The gasholder has spherical shape with a diameter 23 m. How many m3 can hold in?
  14. Air
    air_room_people Room is 26.2 m long, 23.4 dm wide and 628 cm high. How many people can simultaneously be in this room if for hygiene reasons is calculated 5100 dm3 of air per person?
  15. Class
    children_2 In a class are 32 pupils. Of these are 8 boys. What percentage of girls are in the class?
  16. Expressions
    equation Expression (3a-7).(3a+7) is identical with: ?
  17. 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.
  18. Reciprocal
    rec_gamma What is the reciprocal of the sum of the reciprocals of 7 and 2?
  19. Ladislav in Amsterdam
    jakob3 Ladislav was reward and went to conference in Amsterdam. Conferense fee was € 2184. Calculate how many books Ladislav could buy at the price of 42 and 28 euros if he don't want fill whole home library and he can buy only 63 books?
  20. Birthdate
    lizatka Jane on birthday brought 30 lollipops and 24 chewing gum for their friends. How many friends has, if everyone receives the same number of lollipops and chewing gums? How much chewing gum and lollipops got any friend?

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