Examples for 8th grade

Number of problems found: 2711

  • The largest
    cylinder_in_cube The largest possible cylinder was cut from a 20 cm cube. What is the volume of this cylinder?
  • TV tower
    Žižkov_tv_tower Calculate the height of the television tower if an observer standing 430 m from the base of the tower sees the peak at an altitude angle of 23°?
  • Using
    runners Using one of the following forms x+p=q or px=q write an to represent these problems using x as the unknown variable Larry ran 7 more miles than Barry in a month, if Larry ran 20 miles how many did Barry run? please help its due tomorrow
  • Twice of radius
    gule How many times does the surface of a sphere decrease if we reduce its radius twice?
  • Two hemispheres
    hemisphere3 In a wooden hemisphere with a radius r = 1, a hemispherical depression with a radius r/2 was created so that the bases of both hemispheres lie in the same plane. What is the surface of the created body (including the surface of the depression)?
  • Double ratio
    phones The mobile phone was twice gradually discounted in the ratio of 3: 2 1 half: 5 quarters. How much did it originally cost if the price was CZK 4,200 after a double discount?
  • Telegraph poles
    pole The bases of two adjacent telegraph poles have a height difference of 10.5 m. How long do the wires connect the two poles if the slope is 39° 30´?
  • Tourist route
    tourist_1 How long is the tourist route when tourists crossed four-sevenths of the way on foot, crossed the bus twice less than on foot and passed the last 14 kilometers by boat.
  • Pouring alcohol
    roztoky 100 liters of alcohol has 70% How many liters of water need to be added to have 60% alcohol?
  • The hollow cylinder
    duty_valec The hollow cylinder has a height of 70 cm, an outer diameter of 180 cm and an inner diameter of 120 cm. What is the surface of the body, including the area inside the cavity?
  • Art school
    skola_1 Every fifth pupil 9A goes to art school. How many percent of pupils in class 9A go to art school?
  • Coils of transformer
    voltemeter The primary coil of the transformer has 1100 turns and is connected to a voltage of 220V. How many turns does the secondary coil have when the voltage on it is 55 V? Determine the transformation ratio and decide what kind of transformation is it.
  • The field
    tractors 3 tractors plow the field in 6 hours. However, after 2 hours, 1 tractor broke down. How long will the field be plowed?
  • The triangles
    triangle1 The triangles KLM and ABC are given, which are similar to each other. Calculate the lengths of the remaining sides of the triangle KLM, if the lengths of the sides are a = 7 b = 5.6 c = 4.9 k = 5
  • The fastest
    ship The fastest boat can reach speeds more than 710% as fast as the Queen Mary 2. How would you express this number as a fraction and as a decimal?
  • Which
    decanon Which of the following numbers most accurately area of a regular decagon with side s = 2 cm? (A) 9.51 cm2 (B) 20 cm2 (C) 30.78 cm2 (D) 31.84 cm2 (E) 32.90 cm2
  • Diamond area from diagonals
    kosostvorec In the diamond ABCD is AB = 4 dm and the length of the diagonal is 6.4 dm long. What is the area of the diamond?
  • Discount and prices
    sale After a 29% discount, the new product price was € 426. What was the original price of the product?
  • Magnitude of angle
    clocks What magnitude has an obtuse angle enclosed by the hands of clocks at 12:20 hours?
  • In a
    triangles_1 In a triangle, the aspect ratio a: c is 3: 2 and a: b is 5: 4. The perimeter of the triangle is 74cm. Calculate the lengths of the individual sides.

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

We will send a solution to your e-mail address. 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...