If x varies inversely as y and y = 60 when x = 1.5, find x when y = 4.5.

If x varies inversely as y

∴ xy = k (constant)

If x = 1.5 and y = 60

∴

⇒ k = 90

When y = 4.5, then from Eq.(i),

45× y = k

⇒ 45 × y = 90

⇒ 20