A can do a work in 1 day = 1/30 part ⇒ A can do a work in 5 days = 5/30 = 1/6 part ⇒ B can do the same work in 1 day = 1/60 part ⇒ B can do the same work in 5 days = 5/60 = 1/12 part ⇒ Work done by A and B together in 5 days = 1/6 + 1/12 = 3/12 = 1/4 part ⇒ Remaining work = 1 - 1/4 = 3/4 part ∴ Remaining work is 3/4 part.