Equation - examples - page 21

  1. Ring
    prsten The ring made from gold and copper alloy has a weight of 14.5 g and a volume of 1.03 cm3. How much gold and how much copper it contains? The metal densities are Au 19.3 g/cm³ and Cu 8.94 kg·dm-3
  2. RTriangle 17
    rt The hypotenuse of a right triangle is 17 cm. If you decrease both two legs by 3 cm you will reduce the hypotenuse by 4 cm. Determine the length of this legs.
  3. Jane and Miro
    two_men Jane brother Miro is 42 years. And he is three times old as it was Jane when Miro was for so many years as there are now Jane. How old is Jane?
  4. Hockey teams goals
    hockey Hockey teams fired 200 goals. The second team 13 less than first team, third 16 less than the first and fourth tean 19 goals less than first. How many goals fired each team?
  5. Chocholate pyramid
    pyramid_choko How many chocolates are in the third shelf when at the 8th shelf are 41 chocolates in any other shelf is 7 chocolates more the previous shelf.
  6. Three siblings
    brothers Three siblings have birthday in one day-today. Together they have 35 years today. The youngest is three years younger than middle and the oldest is 5 years older than middle. How old is each?
  7. Sides of the triangle
    herons Calculate triangle sides where its area is S = 84 cm2 and a = x, b = x + 1, xc = x + 2
  8. Disease
    kravy Farmers'cooperative had a supply of feed for 50 cows to 6 days. Cows got insidious disease after 4 days, 10 of them died. How many total days that farmers had feed for cows?
  9. Solution
    chemia What amount of 80% solution and what amount of water is needed to mix in order to obtain two liters of 60% solution of this mixture?
  10. Sprinter
    Sprinter Sprinter runs the relay 4 x 400 m to the handover at speed 42 km/h. A second runner is at the start of the handover area 20 m long and runs when it is the first sprinter at distance 10 m. Calculate the speed at which the second runner must run in order to.
  11. The farmer
    kombajn The farmer harvested 840 tons of grain in 2006, which was 44% less than in 2005, and one-fifth more than in 2004. How many tons of grain harvested in years 2005 and 2004?
  12. Passenger car and truck
    2cars From Kutna Hora left at 11:00 clock a truck at 60 km/h. At 12:30 behind him started passenger car at average speed 80 km/h. At what time and how far from Kutna Hora overtake a passenger car truck?
  13. Mean
    integrales if the mean of the set of data 5, 17, 19, 14, 15, 17, 7, 11, 16, 19, 5, 5, 10, 8, 13, 14, 4, 2, 17, 11, x is -91.74, what is the value of x?
  14. Pine
    trees How much of a mixed forest rangers want to cut down, if their head said: "We only cut down pine trees, which in our mixed forest 98%. After cut pine trees constitute 94% of all trees left."
  15. Two pipes
    2pipes One pipe fill one-fifth volume 20 minutes before by second one. The two pipes together will fill the tank in two hours. How long is will fill tank each pipe separately?
  16. Crown coins
    coins_1 Jana saves two-crown and five-crown coins. She has ten coins in the cashier. How many two crowns and how many five crowns shw have if she saved 29 crowns?
  17. Fifth of the number
    numbs_5 The fifth of the number is by 24 less than that number. What is the number?
  18. Book
    matematika_encyklopedia To number pages of thick book was used 4201 digits. How many pages has this book?
  19. Scouts
    skauti_2 Scouts purchased for camp cans two types total cost 1460 CZK. First cans were for CZK 32 and second for 25 CZK. How many cans purchased each type?
  20. Parabola
    parabola_1 Find the equation of a parabola that contains the points at A[6; -5], B[14; 9], C[23; 6]. (use y = ax2+bx+c)

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