Examples for 8th grade - page 86

  1. Apples
    jablka_4 Apples I picked 600 kg this year. Autumn's apples was 4 times more than the summer. How many kg's I picked the summer and how much winter apples?
  2. Raspberries
    maliny_2 Dano had 20 raspberries. John had 90% more raspberries than Dano. Determine how many raspberries have Dano and Juraj together.
  3. Cone
    r_h_cone Calculate the volume of the rotating cone with a base radius 26.3 cm and a side 38.4 cm long.
  4. 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.
  5. Enterprise company
    work 30% of all employees in the enterprise are women. Men are 360 more. How many employees are in the company?
  6. Three-digit
    seven How many three-digit natural numbers do not have the number 7?
  7. Sphere radius
    koule_krychle_2 The surface of the sphere is 60 cm square. Calculate its radius; result round to tenth of cm.
  8. Regular n-gon
    regular_polygons Which regular polygon have a radius of circumscribed circle r = 10 cm and the radius of inscribed circle p = 9.962 cm?
  9. Tank diameter
    cylinder_5 A cylindrical tank has a volume of 60 hectoliters and is 2.5 meters deep. Calculate the tank diameter.
  10. RT perimeter
    rt The leg of the rectangular triangle is 7 cm shorter than the second leg and 8 cm shorter than the hypotenuse. Calculate the triangle circumference.
  11. 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
  12. Ravens
    havrany On two trees sitting 17 ravens. If 3 ravens flew from first to second tree and 5 ravens took off from second tree then the first tree has 2 times more ravens than second tree. How many ravens was originally on every tree?
  13. Tree shadow 3
    tree3_1 A 2-meter rod casts a shadow 3.2 m long. How high is a tree with a shadow of 14.4 m ?
  14. Walnuts
    orechy_2 x walnuts were in the mission. Dano took 1/4 of nuts Michael took 1/8 from the rest and John took 34 nuts. It stayed here 29 nuts. Determine the original number of nuts.
  15. One percent
    led One percent of all the lights in the city are LED, the remaining 99% are conventional. Other types are not there. John counted them honestly but he had counted only conventional. After a good dinner he registered numbers and he have notice that from all t
  16. Efficiency
    rychlovarna-kanvica What is the power output of kettle 2 kW with efficiency 90%?
  17. Unknown number x
    percents2_4 5% from an unknown number equals the number 26. What is the unknown number?
  18. Two ages
    twodigits_1 Gabrielle is 9 years younger than Mikhail. The sum of their ages is 87. What is Mikhail's age?
  19. Volume increase
    basen_6 How many percent will increase in the pool 50 m, width 15m if the level rises from 1m to 150cm?
  20. Two numbers
    fractal_6 The sum of the two numbers is 1. Find both numbers if you know that half of the first is equal to one seventh of the second number.

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.