Work out inverse proportion instantly with clear inputs, formula shown and shareable results.
In inverse proportion the product xy is constant, so y = k/x. Doubling x halves y, which is the behaviour of quantities like speed and journey time or workers and time taken.
Inverse proportion
xy = k, so y₂ = x₁·y₁ / x₂
k = 120 worker-days, so 8 workers need 15 days.
It assumes perfect divisibility of the work. In practice coordination overhead means doubling the workforce rarely halves the time exactly.