VARIATION 1

x is inversely proportional to y. x=18 while y=5. Find y when x is 9.

Solution

x ⍺ k

      y

x = k

      y

18 = k

        5

k = 18 x 5

k = 90

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k = 90, y= ?, x = 9.

x = k

      y

9  = 90

        y

y x 9 = 90  x  y   (multiply by y on both sides)

                y

9y = 90

9      9

Hence y = 10. 

TRY THIS…………….

x is inversely proportional to y. x=80 while y=4. Find y when x is 16.