Examples for 9th grade - page 49

  1. Similarity n-gon
    podobnost 11-gones ABCDEFGHIJK and A'B'C'D'E'F'G'H'I'J'K' are similar. The area of 11-gon ABCDEFGHIJK is S1=254 cm2 and the diagonal length HG is 20 cm. Calculate area of the 11-gon A'B'C'D'E'F'G'H'I'J'K' if H'G' = 36 cm.
  2. Rotation of the Earth
    earth_1 Calculate the circumferential speed of the Earth's surface at a latitude of 53.7°​​. Consider a globe with a radius of 6378 km.
  3. Time gone
    family_6 Square of Richard age equals the age of his mother. When he will bw two times older then his mom will be 7/2 times older than he. How old is Richard and his mom?
  4. Apples 2
    jablka_6 Dried apples contain 15% water. Fresh apples contain 80% water. How many kg of apples we need buy in order to get 3 kg of dried apples?
  5. Frameworks is bad
    space Calculate how many percent will increase the length of an HTML document, if any ASCII character unnecessarily encoded as hexadecimal HTML entity composed of six characters (ampersand, grid #, x, two hex digits and the semicolon). Ie. space as:  
  6. Difference of two number
    squares2_6 The difference of two numbers is 20. They are positive integers greater than zero. The first number raised to one-half equals the second number. Determine the two numbers.
  7. Q of GP
    geometric_1 Calculate quotient of geometric progression if a1=5 a a1+a2=12.
  8. The rectangle
    rectangles_6 Determine the area of the rectangle where the length and width are in the ratio 5:2 and its length is 7.5 cm longer than its width. Determine also its length and its width.
  9. Unknown number x
    percents2_4 5% from an unknown number equals the number 26. What is the unknown number?
  10. Unknown number 4
    ninth I think number. When I divided its square root by its 1/9, I get a number 1. What number am I thinking?
  11. Water in aquarium
    akvarko_4 The aquarium cuboid shape with a length of 25 cm and a width of 30 cm is 9 liters of water. Calculate the areas which are wetted with water.
  12. The car
    cars_4 The car has traveled the distance between A and B for four hour. If we increased the average by 17 km/h the car travel this distance an hour earlier. Determine the initial speed of the car and the distance between A and B.
  13. Factory and divisions
    factory_2 The factory consists of three auxiliary divisions total 2,406 employees. The second division has 76 employees less than 1st division and 3rd division has 212 employees more than the 2nd. How many employees has each division?
  14. Boys and money
    money_12 270 USD boys divided so that Peter got three times more than Paul and Ivan has 120 USD more than than Paul. How much each received?
  15. Boxes
    krabice 200 boxes have been straightened in three rows. The first was 13 more than in the second, and in the second was one fifth more than in the third one. How many boxes are in each row?
  16. Car and cyclist
    cyclist_6 Cyclist started from town at speed 18 km/h. After 1 hour 30 min started the car from town and caught up with the cyclist in 50 minutes. How fast was a car?
  17. Reward
    percents_4 Three workers have shared a common reward 13110 CZK follows: first worker got 35% less than the second and third worker got 20% more than the second worker. How much got each worker?
  18. Price increase 2x
    percents_3 If two consecutive times we increase the price of the product by 20%, how many % is higher final price than the original?
  19. Summer camp
    camp_summer Out of the 180 students at a summer camp, 72 signed up for canoeing. There were 23 students who signed up for trekking, and 13 of those students also signed up for canoeing. Use a two-way table to organize the information and answer the following questio
  20. Sputnik
    sputnik The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800hm/h. How long would it take circle the earth round?

Do you have interesting mathematical example 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 e-mail correctly and check whether you don't have a full mailbox.