Examples for 8th grade - page 64

  1. Rain
    bowl-water How many mm of water rained the roof space 75 m2 if the empty barrel with a radius of 8 dm and height 1.2 m filled to 75% its capacity? :-)
  2. Trapezoid
    lichob_2_1 How long are the trapezoid bases with area 24 cm2 and height 3 cm. One base is 3 times longer than the shorter.
  3. Trams
    trams Tram no. 3,7,10,11 rode together from the depot at 5am. Tram No. 3 returns after 2 hours, tram No. 7 an hour and half, no. 10 in 45 minutes and no. 11 in 30 minutes. For how many minutes and when these trams meet again?
  4. Repairman
    makak Repairman has vowed to do repair work at the plant for 25 days. However work had to be shortened, and therefore he took helper worker. Together they made all the corrections for the whole days. How long it would take work to helper worker?
  5. Three shapes
    three_bodies 1/5 of a circle is shaded. The ratio of area if square to the sum of area of rectangle and that of the circle is 1:2. 60% of the square is shaded and 1/3 of the rectangle is shaded. What is the ratio of the area of circle to that of the rectangle?
  6. Cuboid box
    box How many m2 paper is needed for the sticking cuboid box of dimensions 50 cm, 40 cm and 30 cm? To the folds add one-tenth the area.
  7. Triangle
    heron1 Determine whether a triangle can be formed with the given side lengths. If so, use Heron's formula to find the area of the triangle. a = 177 b = 124 c = 63
  8. Isosceles right triangle
    IsoscelesRightTriangle Contents of an isosceles right triangle is 18 dm2. Calculate the length of its base.
  9. Product - quadratic equation
    circles_3 Product of two numbers is 900. If we increase lowest number by 2 then product will increase by 150. Determine both numbers.
  10. Cuboid - edges
    kvadr The sum of all edges cuboid are 11 meters. However, the width is twice shorter than the length and height is seven times longer than the width. Determine the dimensions of the cuboid.
  11. Fifth of the number
    numbs_5 The fifth of the number is by 24 less than that number. What is the number?
  12. Candies
    bonbons_10 There are two types of candies in the store at 20 CZK/kg and 80 CZK/kg. How much will be cost a mix if we mix 22kg cheaper and 4kg more expensive candies?
  13. Trip
    pomarancovy-dzus On the trip drank 3/10 of pupils tea, 2/5 cola, 1/4 mineral water and remaining 3 juice. How many students were on the trip?
  14. Water lake
    jezirko The length of the lake water is 8 meters width 7 meters and depth 120 centimeters. How many liters of water can fit into the water lake?
  15. Five-digit
    cards Find all five-digit numbers that can be created from numbers 12345 so that the numbers are not repeated and then numbers with repeated digits. Give the calculation.
  16. Diagonal - simple
    makac Calculate the length of the diagonal of a rectangle with dimensions 5 cm and 12 cm.
  17. New computer
    pc_1 New computer process a certain amount of data for 6 hours. For how many hours will process the same amount of data older computer that has a quarter lower performance?
  18. Cuboid - volume, diagonals
    prism_diagonals The length of the one base edge of cuboid a is 3 cm. Body diagonal is ut=13 cm and diagonal of cuboid's baseis u1=5 cm. What is the volume of the cuboid?
  19. Binomials
    two_persons To binomial ? add a number to the resulting trinomial be square of binomial.
  20. Suzan
    eliska My daughter reaches X years in X squared, said Suzan father in 2013 during the celebration of her birthday. When will given fact become reality and how many years at that time will have Suzan?

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.