Examples for 8th grade - page 37

  1. Solution
    chemistry In 469 dl red solution is 84 dl red color and in 102 dl blue solution is 52 dl blue color. How many dl of red and blue dl color solution must be mixed to get a mixture of 247 dl contain 116 dl of color?
  2. Rhombus IV
    image005 Calculate the length of the diagonals of the rhombus, whose lengths are in the ratio 1: 2 and a rhombus side is 35 cm.
  3. Climb
    aircraft_ascend For horizontal distance 4.9 km road rise by 6.1 m. Calculate the road pitch in ‰ (permille, parts per thousand).
  4. Logs
    tramy The log has diameter 30 cm. What's largest beam with a rectangular cross-section can carve from it?
  5. Bus stop
    bus_5 Determine at what time the bus leaves from the bus stop outside the village, if you know that when you leave home at 8:00 and go at speed 3 km/h, you come to a stop 9 minutes after the departure of the bus, and when you go speed at 4 km/h, you come to the
  6. Father and son
    family_17 Father is 48 years old, son 23. When will be the father twice older than a son?
  7. Rotary cylinder
    Povrchy_a_objemy_telies The rotating cylinder has a surface area 69.08 cm2. The area of the shell is 62.8 cm 2. What is the diameter of the cylinder?
  8. The hall
    lucerna The hall had a rectangular ground plan one dimension 20 m longer than the other. After rebuilding the length of the hall declined by 5 m and the width has increased by 10 m. Floor area increased by 300 m2. What were the original dimensions of the hall?
  9. Homework - jumps
    castle_children Sasha jumped 121 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. Raffle
    tombola_tickets In the pool is numbers from 1 to 115. What is the probability that a randomly selected number is not a prime number?
  11. Square and circle
    circle_square Into square is inscribed circle with diameter 10 cm.What is difference between circumference square and circle?
  12. Simple interest
    bank Peter put into bank 790 euros deposit. After 2 years on account overall was 974 euro. What was the interest rate if bank add simple interest?
  13. Tachometer
    tatra-dakar2 Tatra's tachometer shows the initial state 886123 km this morning. Tatra today travel at an average speed of 44 km/h. Determine the function that describes the Tatra's tachometer depending on the time. What is the state of tachometer after 4 hours?
  14. Eight blocks
    cuboids Dana had the task to save the eight blocks of these rules: 1. Between two red cubes must be a different color. 2. Between two blue must be two different colors. 3. Between two green must be three different colors. 4. Between two yellow blocks must be four
  15. Alloy
    hlinik_slitina The first alloy is a mixture of two metals in the ratio 1:2, the second is a mixture of same metals in the ratio 2:3. At what ratio we have these two alloys put into the furnace to obtain a new metal alloy with ratio 17:27? (All three ratios correspond to.
  16. Arc
    angles Convert to arc measures (radians): 924 ° Result write as a multiple of π
  17. 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.
  18. Two workers
    safarik_stu Two workers make 138 parts/items. The first one produces 30% more than the second. How many items will each produce?
  19. Pytagoriade
    pytagoriada Two fifth-graders teams competing in math competitions - in Mathematical Olympiad and Pytagoriade. Of the 33 students competed in at least one of the contest 22 students. Students who competed only in Pytagoriade was twice more than those who just competed
  20. Workhorses
    work A team of colleagues done the work in 20 days. After adding 2 colleagues from the beginning the work was completed in 15 days. How many members has the colleague team?

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