We show that if R is an exchange ring, then the following are equivalent: (1) R satisfies related comparability. (2) Given a , b , d ∈ R with a R + b R = d R , there exists a related unit w ∈ R such that a + b t = d w . (3) Given a , b ∈ R with a R = b R , there exists a related unit w ∈ R such that a = b w . Moreover, we investigate the dual problems for rings which are quasi-injective as right modules.