If x and y vary inversely and x = 18 when y = 8, find x when y = 16.
∴ x and y are inversely and x = 18, y = 8
∴ xy = 18 × 8 = 144
Now if y = 16, then x=14416=9
If x and y vary inversely and x = 15 when y = 6, find y when x = 9.