Examples for 9th grade - page 52

  1. Reduce of the volume
    cubes Calculate how many % reduce the volume of the cube is we reduced length of each edge by 10%.
  2. Crates 2
    bedny In 6 crates is 45 kg of apples In  5 crates is equally In 1 in crate is 3 kg more How many kilograms in each crate?
  3. Stamps and albums
    stamp Michail has in three albums stored 170 stamps. In the first album, there are 14 more than in the second and in the second is by 1/5 less than in the third. How many stamps are in the first album?
  4. Gold coin
    gold_munzen Gold coin contains 964 promile pure gold, which is 7.16 g. What is the weight of coin in grams?
  5. Shepherd
    sheep_1 The shepherd has fewer than 500 sheep; where they can be up to 2, 3, 4, 5, 6 row is always 1 remain, and as can be increased up to 7 rows of the sheep, and it is not increased no ovine. How many sheep has a shepherd?
  6. Bob and Bobek
    bob_a_bobek At 10h 20min runs Bobek from hat at average speed 12 km/h. At what time must run out Bob at speed 18 km/h to catch him 9 kilometers from the hat?
  7. Double-track
    vlak_1 On double-track express met with a freight train. Express travel at speed 72 km/h, a freight train at speed 36 km/h. After what time period will be from 9 km apart?
  8. High wall
    mur I have a wall 2m high. I need a 15 degree angle (upward) to second wall 4 meters away. How high must the second wall?
  9. Siblings
    tri-sourozenci Three siblings had saved up a total of 1,274 CZK. Peter had saved up to 15% more than Jirka and Hanka 10% less than Peter. How much money they saved each one of them?
  10. Grid/network of cube
    siet_kocky Grid of cube has a circumference 42 mm. Calculate the surface area of the cube ...
  11. Powers
    1power Express the expression ? as the n-th power of the base 10.
  12. Regular triangular prism
    3b_hranol Calculate the surface area of body of regular triangular prism, when the length of its base edge is 6.5 cm and height 0.2 m.
  13. Parallelogram ABCD
    paralleogram_1 The area of parallelogram ABCD is 440 cm2. Points M and N are the midpoints of the sides AB and BC. What is the area of a quadrilateral MBND?
  14. Fraction
    polynomial For what x expression ? equals zero?
  15. Tree shadow
    tree3 The shadow of the tree is 16 meters long. Shadow of two meters high tourist sign beside standing is 3.2 meters long. What height has tree (in meters)?
  16. Chord 4
    circles_5 I need to calculate the circumference of a circle, I know the chord length c=22 cm and the distance from the center d=29 cm chord to the circle.
  17. Series
    fib Your task is express the sum of the following arithmetic series for n = 14: S(n) = 11 + 13 + 15 + 17 + ... + 2n+9 + 2n+11
  18. Basketball
    friends_1 Peter and Franta threw to the basket. Each had 20 attempts. Peter scored thirteen and twelve Franta. Give them success in percentage.
  19. Internal and external angles
    inner_outer_angles_triangle Calculate the remaining internal and external angles of a triangle, if you know the internal angle γ (gamma) = 34 degrees and one external angle is 78 degrees and 40 '. Determine what kind of triangle it is from the size of its angles.
  20. The tent
    stan The tent shape of a regular quadrilateral pyramid has a base edge length a = 2 m and a height v = 1.8 m. How many m2 of cloth we need to make the tent if we have to add 7% of the seams? How many m3 of air will be in the tent?

Do you have an interesting mathematical word problem that you can't solve it? Enter it, and we can try to solve it.



To this e-mail address, we will reply solution; solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...