VARIATION H1

 x is inversely proportional to y. x=18 while y=5. Find y when x is 30.

 

Solution

 

x ⍺ k

      y

 

x = k

      y

 

18 = k

        5

 

k = 18 x 5

 

k = 90

 

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 

k = 90, y= ?, x = 30.

 

x = k

      y

 

30 = 90

         y

 

y x 30 = 90  x  y   (multiply by y on both sides)

                y

 

 

30y = 90

30      30

 

Hence y = 3  .

 

 

TRY THIS…………….

 

 

x is inversely proportional to y. x=120 while y=4. Find y when x is 10.