A man can row a boat at 20 kmph in still water. If the speed of the stream is 5 km h, what is the time taken to row a distance of 75 km downstream? code example

Example: A boat covers a certain distance downstream in 1 hour, while it comes back in 1 hour 40 min. If the speed of the stream be 5 kmph, what is the speed of the boat in still water?

A boat covers a certain distance downstream in 1 hour, while it comes back in 1 hour 40 min. If the speed of the stream be 5 kmph, what is the speed of the boat in still water?