A runs \(1 {2 \over 3}\) times as fast as B. If A gives B a start of 80 m, how far must the winning post be so that A and B might reach it at the same time?

A boat covers 12 km upstream & 18 km downstream in 3 hrs, while it covers 36 km upstream & 24 km downstream in 6.5 hrs. What is the speed of the current?

If 'A' is 7 times as efficient as 'B', 'B' takes 32 days to complete the task, then find the number of days required to finish the whole work by 'A' and 'B' working together.