The most difficult problems

Number of problems found: 7295

  • Taxi
    linear_eq A taxi ride costs $3 plus $2.50 per mile. Write and Graph an equation in two variables that represent the total cost of a taxi ride.
  • Cancel fractions
    zlomky Compress the expression of factorial: (n+6)!/(n+4)!-n!/(n-2)!
  • Normal distribution GPA
    normal_d The average GPA is 2.78 with a standard deviation of 4.5. What are students in the bottom the 20% having what GPA?
  • Overload
    aircraft-02 What overload in g (g-force) has passed the pilot if he accelerated from 0 to 600 km/h in 3 seconds?
  • The Scout Tent
    jehlan_4b_obdelnik The Scout Tent has a rectangular wooden underlay with dimensions of 220 cm and 150 cm. How much canvas is needed for a 170 cm high pyramid roof?
  • Hypotenuse - RT
    triangle_bac A triangle has a hypotenuse of 55 and an altitude to the hypotenuse of 33. What is the area of the triangle?
  • Hexagon ABCDEF
    hexagon In the regular hexagon ABCDEF, the diagonal AE has a length 8cm. Calculate the circumference and the hexagon area.
  • The sides
    rectangle The sides of a rectangle are in a ratio of 2:3, and its perimeter is 1 1/4 inches. What are the lengths of its side? Draw it.
  • Right angled triangle 3
    right_triangle Side b = 1.5, hypotenuse angle A = 70 degrees, Angle B = 20 degrees. Find its unknown sides length.
  • Coordinates of the vertices
    troj Calculate the coordinates of the vertices of a triangle if the equations of its sides are 7x-4y-1 = 0 x-2y + 7 = 0 2x + y + 4 = 0
  • Water flow 2
    water3 How many litres of water will flow in 7 minutes from a cylindrical pipe 1 cm in diameter, if the water flows at a speed of 30 km per hour
  • Train speed
    trains Two guns were fired from the same place at an interval of 10 minutes and 30 seconds, but a person in a train approaching the place hears second shot 10 minutes after the first. The speed of the train (in km/hr), supposing that sound travels at 340 m/s is:
  • The diamond
    kosodlznik The diamond has sides of 35 cm and the diagonals are in a ratio of 1: 2. Calculate the lengths of the diagonals.
  • Exponential warm
    teplomer Suppose that a body with temperature T1 is placed in surroundings with temperature T0 different from that of T1. The body will either cool or warm to temperature T(t) after time t, in minutes, where T(t)=T0 + (T1-T0)e^(-kt) . If jello salad with 30 degree
  • Diagonal to area
    rectangle Calculate the area of a rectangle in which the length of the diagonal is 10 cm.
  • Radioactive material
    radium A radioactive material loses 10% of its mass each year. What proportion will be left there after n=6 years?
  • Two chords
    chords In a circle with a radius of 8.5 cm, two parallel chords are constructed, the lengths of which are 9 cm and 12 cm. Find the distance of the chords in a circle.
  • Equilateral triangle
    vpisany_stvorec A square is inscribed into an equilateral triangle with a side of 10 cm. Calculate the length of the square side.
  • Ruler and compass
    triangle_bac Use a ruler and compass to construct a triangle ABC with AB 5cm BAC 60° and ACB 45°.
  • Bitoo and Reena
    apples Bitoo ate 3/5 part of an apple and the remaining part was eaten by his sister Reena. How much part of an apple did Renna eat? Who had the larger share? By how much?

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