The mean of the 5 smallest numbers from a group is 15 while the mean of all the 13 members of the group taken together is 17. What is the mean of the 8 largest numbers?
Josna takes 4 hrs 30 min in walking a distance and riding back to some place where she started. She could walk both ways in 5 hrs 40 min. The time taken by her to ride back both ways is