Mathematics

Question

y varies jointly as x and z. If y = 5 when x = 3 and z= 4, find y when x = 6 and z = 8.

1 Answer

  • Answer:

    y = 20

    Step-by-step explanation:

    Given y varies jointly as x and z then the equation relating them is

    y = kxz ← k is the constant of variation

    To find k use the condition y = 5 when x = 3 and z = 4

    5 = k × 3 × 4 = 12k ( divide both sides by 12 )

    [tex]\frac{5}{12}[/tex] = k

    y = [tex]\frac{5}{12}[/tex] xz ← equation of variation

    When x = 6 and z = 8 , then

    y = [tex]\frac{5}{12}[/tex] × 6 × 8 = [tex]\frac{5}{12}[/tex] × 48 = 5 × 4 = 20

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