Mathematics for IGCSE & O level - Proportion (Section 2 - No. 4)

If *p* varies inversely with the square of *q*, then when *q* is doubled, *p* is:

halved

doubled

quartered

multiplied by 4

p = k/q^2. If q becomes 2q, then p' = k/(2q)^2 = k/4q^2, which is 1/4 of the original p.