Examples for 9th grade - page 63

  1. Class pairs
    pair_1 In a class of 34 students, including 14 boys and 20 girls. How many couples (heterosexual, boy-girl) we can create? By what formula?
  2. Nuts
    orechy Peter has 49 nuts. Walnuts have 3 more than hazelnuts and hazelnut 2 over almonds. Determine the number of wallnuts, almonds and hazelnuts.
  3. Principal and interest
    bank_pig Peter put € 270 principal into bank and at the end of the year on account was € 282. To what annual interest rate that Peter had deposited money in the bank?
  4. Roof tiles
    Lichobeznik_strecha The roof has a trapezoidal shape with bases of 15 m and 10 m, height of roof is 4 meters. How many tiles will need if on 1 m2 should be used 8 tiles?
  5. Diagonals
    stvorec_7 Draw a square ABCD whose diagonals have a length of 6 cm
  6. Hexagon rotation
    hexagnos A regular hexagon of side 6 cm is rotated through 60° along a line passing through its longest diagonal. What is the volume of the figure thus generated?
  7. Concentration
    hcl_1 How many grams of 65% and 50% acid is to be mixed to give 240 g acid with a concentration of 60%?
  8. Cuboid walls
    cuboid_9 Calculate the volume of the cuboid if its different walls have area of 195cm², 135cm² and 117cm².
  9. Mom and daughter
    family_1 Mother is 39 years old. Her daughter is 15 years. For many years will mother be four times older than the daughter?
  10. Sales stores
    map_2 The first sales store passed the 1/3 and the second 2/5 of the total amount of goods.In third store passed the 2/3 rest of the goods. The remaining 40 kg of goods put into fourth store. How many kilograms of goods pass to a third store?
  11. Isosceles trapezoid
    lichobeznik_6 In an isosceles trapezoid KLMN intersection of the diagonals is marked by the letter S. Calculate the area of trapezoid if /KS/: /SM/ = 2:1 and a triangle KSN is 14 cm2.
  12. Real estate
    house Residential house has three entrances numbered by odd numbers arithmetic progression. The sum of the two numbers on the corner entrances is 50. Calculate the highest of this three numbers.
  13. Mass
    tubes The thickness of a metallic tube is 1cm and its outer radius is 11cm. Find the mass of such 1m long tube, if the density of the metal is 7.5g per cubic cm.
  14. 3s prism
    Prism It is given a regular perpendicular triangular prism with a height 19.0 cm and a base edge length 7.1 cm. Calculate the volume of the prism.
  15. PIN - codes
    pin How many five-digit PIN - code can we create using the even numbers?
  16. Numbers
    primes Write smallest three-digit number, which in division 5 and 7 gives the rest 2.
  17. Square roots
    roots What is equal to the product of the square roots of 540225?
  18. Password dalibor
    lock Kamila wants to change the password daliborZ by a) two consonants exchanged between themselves, b) changes one little vowel to such same great vowel c) makes this two changes. How many opportunities have a choice?
  19. Store
    img-thing Peter paid in store 3 euros more than half the amount that was on arrival to the store. When he leave shop he left 10 euros. How many euros he had upon arrival to the store?
  20. Unknown number 10
    num_1 Number first increased by 30%, then by 1/5. What percentage we've increased the original number?

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