Examples for 8th grade - page 77

  1. Cuboid - ratios
    kvader11 The sizes of the edges of the cuboid are in the ratio 2: 3: 5. The smallest wall have area 54 cm2. Calculate the surface area and volume of this cuboid.
  2. Blueberries 2
    boruvky_2 Lenka and Martin collected eight liters of blueberries in two hours. How long will take to collect blueberries by Lenka itself, if we know that she collect all 2.5 hours less than Martin?
  3. Sales off
    save_now Calculate what was the original price of the good, if the price after discount 25% and the subsequent rise of 20% is 400 USD.
  4. 2d shape
    semicircles_rect Calculate the content of a shape in which an arbitrary point is not more than 3 cm from the segment AB. The length of the segment AB is 5 cm.
  5. Unknown number
    nums Identify unknown number which 1/5 is 40 greater than one tenth of that number.
  6. Trapezoid MO-5-Z8
    lichobeznik-stredni_pricka_2 Trapezoid KLMN has bases 12 and 4 cm long. The area of triangle KMN is 9 cm2. What is the area of the trapezoid KLMN?
  7. Combinations of sweaters
    sveter I have 4 sweaters two are white, 1 red and 1 green. How many ways can this done?
  8. Flowerbed
    tulipany Family cultivated tulips on a square flower bed of 6 meters. Later they added the square terrace with a side of 7 meters to their house. One vertex of the terrace lay exactly in the middle of a tulip bed, and one side of the terrace divided the side of the
  9. Log
    5962705_ad Worker cut his thick log to 6 pieces for 30 min. How long he cut log to 12 pieces?
  10. Addends
    two Number 118 divide into two addends, so first addend is 69 greater than 75% of the second addend.
  11. Megapascals
    engine What is the area of crosssection of the piston, if the force of 300 kN produces a pressure of 5 MPa?
  12. Potatoes
    zemiaky_3 Daniela and Michael would jointly dug potatoes for 7.5 hours. But if Daniela was working alone she would take 2.5 hours more as if he were working with Michael. Determine how much for the work done by Michael himself and how much Daniela herself.
  13. Assistant
    psaci-stroj Assistant rewrote 15% of the entire manuscript in 12 hours. How many hours must still write to rewrite the rest of the manuscript?
  14. Theatro
    divadlo_1 Theatrical performance was attended by 480 spectators. Women were in the audience 40 more than men and children 60 less than half of adult spectators. How many men, women and children attended a theater performance?
  15. Z7-I-4 stars 4949
    hviezdicky_mo Write instead of stars digits so the next write of product of the two numbers to be valid: ∗ ∗ ∗ · ∗ ∗ ∗ ∗ ∗ ∗ ∗ 4 9 4 9 ∗ ∗ ∗ ∗ ∗ ∗ 4 ∗ ∗
  16. Trams
    tramvaje Two trams started at the same time from the same place. One tram journey takes 30 minutes and the second 45 minutes to its final stop. How long will trams meet again?
  17. Pool
    bazen-2-05_1 The pool has the shape of a cylinder with a diameter 4.6m, the presumed height is 130cm. The bucket fits 12l of water. How many buckets do you have to bring to fill this pool?
  18. Book read
    books_12 If Petra read 10 pages per day, she would read the book two days earlier than she read 6 pages a day. How many pages does a book have?
  19. Base, percents, value
    percent_1 Base is 344084 which is 100 %. How many percent is 384177?
  20. Plum
    plumbs_1 On the platter are plum. How many were there if its have to be able to share equally among 8,10 and 12 children?

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