Latest problems - page 18

  1. Prove
    two_circles_1 Prove that k1 and k2 is the equations of two circles. Find the equation of the line that passes through the centers of these circles. k1: x2+y2+2x+4y+1=0 k2: x2+y2-8x+6y+9=0
  2. CuSO4 mixture
    chemia_2 How many grams of solid CuSO4 we have to add to 450g of 15% CuSO4 solution to produce a 25% solution?
  3. Sum of inner angles
    angle-sum-of-polygon Prove that the sum of all inner angles of any convex n-angle equals (n-2) . 180 degrees.
  4. The big clock
    hodiny_4 The big clock hands stopped at a random moment. What is the probability that: a) a small hand showed the time between 1:00 and 3:00? b) the big hand was in the same area as a small hand in the role of a)? c) did the hours just show the time between 21:00.
  5. Sandbox
    sand_2 Sandbox has area of 32 sq ft and length of 4 1/2 ft. What is width of sandbox.
  6. Digits
    seq_5 Show that if x, y, z are 3 consecutive nonzero digits, zyx-xyz = 198, where zyx and xyz are three-digit numbers created from x, y, z.
  7. Geometric progression 4
    square_rot_1 8,4√2,4,2√2
  8. Algebra
    parabol_3 X+y=5, find xy (find the product of x and y if x+y = 5)
  9. Intersections
    linearna Find the intersections of the function plot with coordinate axes: f (x): y = x + 3/5
  10. 5 people
    penize_49 5 people have $122000 and 1 person has $539000 How much should each person (equally) pay?
  11. Length subtracting
    meter_11 Express in mm: 5 3/10 cm - 2/5 mm
  12. Simplify 3
    fractal_14 Simplify mixed numerals expression: 8 1/4- 3 2/5 - (2 1/3 - 1/4) Show your solution.
  13. Adding mixed numerals
    zlomky_18 3 3/4 + 2 3/5 + 5 1/2 Show your solution.
  14. Utopia Island
    doktori A probability of disease A on the island of Utopia is 40%. A probability of occurrence among the men of this island, which make up 60% of all the population (the rest are women), is 50%. What is the probability of occurrence of A disease among women on Uto
  15. Performance
    workers_42 Two masons with the same performance would have made of plaster for 6 days. One of them, however, has increased its daily performance by 50%. How long would take they now to make plaster together?
  16. The perimeter
    hexagon6 The perimeter of equilateral △PQR is 12. The perimeter of regular hexagon STUVWX is also 12. What is the ratio of the area of △PQR to the area of STUVWX?
  17. Bulbs
    bulbs_2 There are 875 identical light bulbs in the sports hall lightning for 2 hours. How long does it lightning 100 this light bulbs?
  18. Angle of diagonal
    hranol_9 Angle between the body diagonal of a regular quadrilateral and its base is 60°. The edge of the base has a length of 10cm. Calculate the body volume.
  19. 75th percentile (quartille Q3)
    statistics Find 75th percentile for 30,42,42,46,46,46,50,50,54
  20. Sand path
    sand_1 How many m3 of sand is needed to fill the 1.5m wide path around a rectangular flowerbed of 8m and 14m if the sand layer is 6cm high?

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