maths

posted by .

if x and y vary inversely and x=18 when y=8,find x when y=16

  • maths -

    x and y vary inversely ---y = kx , where k is a constant
    given: x=18, y = 8
    8 = 18k
    k = 4/9

    so y = (4/9)x or 9x = 4y
    when y = 16
    9x = 4(16)
    x = 64/9

    or

    x1/y1 = y2/x2

    18/8 = 16/x2
    18x2 = 8(16)
    x2 = 8(16)/18 = 64/9

  • maths -

    eh? inversely ==> xy = k

    8*18 = k
    k = 144

    when y=16,
    x*16 = 144
    x = 9

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    Suppose that x and y vary inversely and that y=1/6 when x = 3. Write a function that models the inverse variation and find y when x = 10.
  2. Inverse Variation

    Help me please.. Explain also :( 1. E is inversely proportional to Z and Z = 4 when E = 6. 2. P varies inversely as Q and Q = 2/3 when P = 1/2. 3.R is inversely proportional to the square of I and I = 25 when R = 100. 4. F varies inversely …
  3. Algebra 2

    On some tubes of caulking, the diameter of the circular nozzle opening can be adjusted to produce lines of varying thickness. The table shows the length (L) of caulking obtained from a tube when the nozzle opening has diameter (d) …
  4. Science

    What is the relationship between the number of gas particles and pressure. Are these two variables directly proportional or do they vary inversely?
  5. Alegrbra 1

    x and y vary inversely, and y = 3 when x = 6. Find y when x = 9. A. 2 B. 4.5 C. 12 D. 18
  6. Pre-Algebra

    If y varies directly with x, find the constant of variation with x = 4 and y = -24 If y varies inversely with x, find the constant of variation with x=5 and y = 10 If y varies directly with x, and y = 35 when x = 5 , find x when y …
  7. Alg 2 HELP!!

    1.) Find an exponential function of the form y=ab^x whose graph passes through the points (2,48) and (5,3072) 2.) The variables x and y vary inversely. Use the given values to write an equation relating x and y. Then find y when x=3. …
  8. Math/Algebra

    Im stuck on two problems and would really appreciate the help. 1. y varies jointly as a and b, and inversely as the square root of c. y=28 when a=2, b=7, and c=9. Find y when a=4, b=2, and c=4 2. y varies directly as x and inversely …
  9. math

    The variables x and y vary inversely. When y is 24, x is 8. What is y when x is 4?
  10. Algebra2

    suppose c and d vary inversely and d=2 when c=17 write an equation that models that variation find d when c=68

More Similar Questions