A and B, working together, can complete a work in d days. Working alone, A takes (8 + d) days and B takes (18 + d) days to complete the same work. A works for 4 days. The remaining work will be completed by B alone in?

24 days

d = \(\sqrt {8 × 18 }\)                   

d = \(\sqrt {144 }\)                           

d = 12

A = 8 + d = 8 + 12 = 20

B = 18 + d = 18 + 12 = 30

A's 4 days work = 3 × 4 = 12

Remaining work = 60 - 12 = 48

B finish the remaining work in = \(\frac{48}{2}\) = 24 days