'A' and 'B' together can do a piece of work in 15 days while 'B' and 'C' together can do the same work in 12 days. 'A' started the work alone and worked on it for 1 day, then 'B' alone worked on it for 8 days and 'C' alone completed the remaining work in 14 days. Find the time taken by 'B' alone to complete the whole work.