Pipe A can fill a tank in 16 minutes and pipe B can empty it in 24 minutes. If both the pipes are opened together after how many minutes should pipe B be closed, so that the tank is filled in 30 minutes?

A tiger is 50 of its own heaps behind a deer. The tiger takes 5 heaps per minute to the deer’s 4. If the tiger & the deer cover 8 m & 5 m per heap respectively. What distance will the tiger have to run before it catches the deer?