A and B can together complete a task in 18 hours. After 6 hours A leaves. B takes 36 hours to finish rest of the task. How many hours would A have taken to do the task if he worked alone?
The average age of 120 members of a society is 60.7 years. By addition of 30 new members, the average age becomes 56.3 years. What is the average age (in years) of newly joined members?
S does half as much work as T in 1/7 of the time taken by T. If together they take 21 days to complete a work, then how may days shall S take to complete that work alone?