Examples for 8th grade - page 28

  1. Mother and daughter
    kresba_1 The ratio of years mother and daughter is 5:2. After 7 years the ratio is 2: 1. How many years ago daughter was born?
  2. Millionaire
    money_7 Mr. Smith have gone withdraw from bank saving interest € 1,500. How big was his initial deposit if the annual interest rate is 1.5%?
  3. Two looms
    stav On two different looms with different performance can be make required quantity of textile in 6 hours when both work together. On the first machine this quantity of the textile can make in 10 hours. How long should take make same quantity of textile on a s
  4. Similarity
    podobnost ABC is a triangle wherein a = 4 cm, b = 6 cm, c = 8 cm. Is it similar to the triangle DEF: d = 3 cm, e = 4.5 cm, f = 6 cm? If so, determine the ratio of similarity.
  5. Hřiště
    playground Map scale is 1: 1000. The playground is rectangular and on the map has dimensions 10 cm and 5 cm What is area of playground in square meters in reality?
  6. Leveling
    quattro Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 28 m2 to the "height" 12 mm if consumtion is 1.7 kg per square meter and millimeter thickness.
  7. Comparing powers
    diagram How many times is number 55 larger than number 45?
  8. Sawdust
    drevo_kmen_rez How many cubic centimeters of wood sawdust is created by cut the tree trunk with a diameter of 38 cm and when the gap width is 6 mm?
  9. Homework - jumps
    castle_children Sasha jumped 142 cm Peter 4 cm more than Jirka. Jirka 6 cm less than Misha. Misha 7 cm less than Filip and Filip half as much Sasha and Petr together. How far each jumped?
  10. Pool
    bazen Mr. Peter build a pool shape of a four-sided prism with rhombus base in the garden. Base edge length is 6 m, distance of the opposite walls of the pool is 5 m. Estimated depth is 193 cm. How many hectoliters of water consume Mr. Peter to fill the pool?
  11. Square
    square_1 Points A[1,5] and B[-4,-5] are adjacent vertices of the square ABCD. Calculate area of the square ABCD.
  12. Kitchen
    valcek_na_cesto Kitchen roller has a diameter 85 mm and width of 337 mm. How many square millimeters roll on one turn?
  13. Gear wheels
    gear Two gear wheels, which fit together have number of teeth z1=132 and z2=123. Calculate the speed of the first wheel, if the second wheel rotates 247 revolutions per minute.
  14. Event probability
    dices_1 The probability of event G in 9 independent experiments is 0.48. What is the probability that the event G occurs in one experiment (probability is same)?
  15. Rectangle
    obdlznik_torta Area of rectangle is 1430. Its length is 29 larger than the width. What are the dimensions of the rectangle?
  16. Ladder
    rebrik_3 Ladder 10 meters long is staying against the wall so that its bottom edge is 6 meters away from the wall. What height reaches ladder?
  17. Cows
    cow_3 Agricultural cooperative has increased the number of housed cows by 14% to 285 units. By how many cows increased agricultural cooperative the number of cows?
  18. Pumps
    pumps Five pumps pumped 1,800 hl of water for 3 hours. How many hectoliters of water pump same two powerful pumps for six hours?
  19. Probability - tickets
    zreby What is the probability that when you have 25 tickets in 5000 that you wins the first (one) prize?
  20. 3sides prism
    prism_3 The base of vertical prism is an isosceles triangle whose base is 10 cm and the arm is 13 cm long. Prism height is three times the height of base triangle. Calculate the surface area of the prism.

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