A man travels 15 km towards east, then turns right and travels 20 km. He then turns left and travels 30 km. Finally, he takes a right turn and covers 40 km. The shortest distance between the starting point and the destination is:
If an anchored boat is rocked by waves whose crests are 80 m apart and whose velocity is 20 m/s, then the time required by the crests to reach the boat is _______.
A and B can complete a task in 40 days, B and C can complete it in 30 days while C and A can complete the same task together in 24 days. How many days will each of A, B and C take to complete the task individually?