Two men each have a mass of 90 kg. If the gravitational force between them is 8.64 10-8 N, how far apart are they? G = 6.67 * 10-11 N⋅ (m/kg) 2

Applicable formular:

F = Gm1m2/d^2, where F = gravitational force, m1 & m2 = mass of the two bodies, G = Gravitational constant, d = distance between the bodies.

Substituting;

8.64*10^-8 = (6.67*10^-11*90*90) / d^2

d^2 = (6.67*10^-11*90^2) / (8.64*10^-8)

d = Sqrt [ (6.67*10^-11*90^2) / (8.64*10^-8) ] = 2.5 m

The two men are 2.5 m apart.