Examples for 8th grade - page 70

  1. Boys and girls 2
    boy_2 The ratio of boys to girls in math club is 4:3 . After 8 more girls joined the Club, the ratio become 1:1. How many members are there in the club now?
  2. Four circles
    circles_2 1) Calculate the circle radius if its area is 400 cm square 2) Calculate the radius of the circle whose circumference is 400 cm. 3) Calculate circle circumference if its area is 400 cm square 4) Calculate the circle's area if perimeter 400 cm.
  3. Mow the lawn
    grass_2 Dano would mow the lawn in 12 hours and Milada in 16 hours. How long will take the lawn mow together?
  4. Candies
    bonbon If Alena give Lenka 3 candy will still have 1 more candy. If Lenka give Alena 1 candy Alena will hame twice more than Lenka. How many candies have each of them?
  5. Driver
    truck_2 The driver of the supply car reckoned that at the average speed of 72 km/h arrives to the warehouse for 1 1/4 hours. After 30 km however unintentionally drove to the gas station and have ten minutes delay. At what average speed would have to go the rest.
  6. Gasoline tank cylindrical
    cisterna What is the inner diameter of the tank, which is 8 m long and contains 40 cubic cubic meters of gasoline?
  7. Octagonal mat
    8gon_1 Octagonal mat formed from a square plate with a side of 40 cm so that every corner cut the isosceles triangle with leg 3.6 cm. What is the content area of one mat?
  8. Positive number z
    137977724_4c6058fe95_m Positive number z is 10% greater than the number y. How many % is y smaller than z? Report the result rounded to one decimal place.
  9. Divisibility
    numbers_29 Write all the integers x divisible by seven and eight at the same time for which the following applies: 100
  10. Dining room
    table The dining room has 11 tables (six and eight seats). In total there are 78 seats in the dining room. How many are six-and eight-seat tables?
  11. Container
    valec2_5 The container has a cylindrical shape the base diameter 0.8 m and the area of the base is equal to the area of the wall. How many liters of water can we pour into the container?
  12. One million
    million Write the million number (1000000) by using only 9 numbers and algebraic operations plus, minus, times, divided, powers, and squares. Find at least three different solutions.
  13. The tram
    elektricky_1 The tram is moving with acceleration a = 0.3m/s2. How long it will pass the first meter of track? How long does it take 10 meters. What is its speed at the end of the 10 meters track?
  14. Reducing number
    123 Reducing the an unknown number by 28.5% we get number 243.1. Determine unknown number.
  15. Three friends
    money_19 Three friends divided the profit 104,650 CZK, so that for every 4 CZK, which got the first friend equals 5 crowns for second and for every 9 CZK, which got the second equals 16 CZK for third. Question: Who got the most and how much.
  16. Truncated cone 5
    truncated_cone The height of a cone 7 cm and the length of side is 10 cm and the lower radius is 3cm. What could the possible answer for the upper radius of truncated cone?
  17. Concrete pipe
    beton-skruz How much will cost cover a 6 m long concrete pipe with an outer radius 1.5 m and inner radius 0.8 meters if 1 m2 paint costs 24 €.
  18. Store
    img-thing Peter paid in store 3 euros more than half the amount that was on arrival to the store. When he leave shop he left 10 euros. How many euros he had upon arrival to the store?
  19. Rectangle - sides 4
    mouse Perimeter of the rectangle is 72 cm. Calculate the length of the sides that are in the ratio 3:5.
  20. Internal angles
    angle_3 One internal angle of the triangle JAR is 25 degrees. The difference is the size of the two other is 15°. Identify the size of these angles.

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