Examples for 8th grade - page 63

  1. Mushrooms
    mushrooms-01 For five days, we have collected 410 mushrooms. Interestingly every day we have collected 10 mushrooms more than the preceding day. How many mushrooms we have collected during 4th day?
  2. Loan
    money_2 If you take a bank loan $ 24000 and we want to repay after the year, we have to pay the total amount $ 24696/ What is the annual interest rate on this loan?
  3. Cube volume
    cube6 The cube has a surface of 384 cm2. Calculate its volume.
  4. Two rooms
    clean_1 Woman cleans the room in 30 minutes a man in 90 minutes. How long will take they clean two rooms?
  5. Sines
    sines In ▵ ABC, if sin(α)=0.5 and sin(β)=0.1 calculate sin(γ)
  6. Car
    sanitka_1 Car goes some distance in 3 hours and 20 minutes. If it increase speed by 10 km/h, i goes this distance in 2.5 hours. Calculate the distance.
  7. Diagonals
    stvorec_7 Draw a square ABCD whose diagonals have a length of 6 cm
  8. Diagonal - simple
    makac Calculate the length of the diagonal of a rectangle with dimensions 5 cm and 12 cm.
  9. Apprentice
    ucen Worker and apprentice execute the work for 6 hours. Worker performs himself in 10 hours. How long do the work of an apprentice?
  10. Saving
    2kc Paul save 155Kč in 46 2 Kc and 5Kc coins. How much saved 2Kc and 5Kc coins?
  11. Sea water
    salt_5 One tonne of sea water contains 25 kg of salt. How many tonnes of sea water need to be evaporated to obtain 1 tonne of salt?
  12. Meat
    maso Half a kilogram of pork and three-quarters of a kilogram of beef cost total 6.6 USD. One quarter of a kilogram of beef and 1 kilogram of pork cost 6.3 USD. Determine the price of 1 kg of each type of meat.
  13. Mason with assistant
    workers_15 Mason had to complete the work in 10 days. Two and a half days later his assistant arrived. Together they completed the work in next three and a half days. How many days would he need an assistant for the same work?
  14. Book
    books_1 Alena read a book at speed 15 pages per day. If she read twice as fast she should read a book four days earlier. How many pages have a book?
  15. After 16 years
    diana After 16 years will Dana be five times older as she was four years ago. After how many years will Dana celebrate her 16th birthday?
  16. Heating plant
    coal_1 Workers dump imported coke at heating plant. On the first day used half of the amount, the second day three quarters the rest and on the third day left 120 tons. How much coke they dump at heating plant?
  17. Probability - tickets
    zreby What is the probability that when you have 25 tickets in 5000 that you wins the first (one) prize?
  18. Shoes and slippers
    prezuvky Shoes were three times as many as slippers. If shoes were cheaper by 120, it would be twice as expensive as slippers. How much cost shoes and how much slippers?
  19. Cube 5
    cube_4 The surface of the cube is 15.36 dm2. How will change the surface area of this cube if the length of the edges is reduced by 2 cm?
  20. Grandmother
    cukriky_3 Grandmother wants to give the candies to grandchildren that when she gives 5 candy everyone 3 missing and when she gives 4 candies 3 is surplus. How many grandchildren has grandmother and how many candies has?

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.