There is a boat with speed 17 kmhr. The stream has a speed of x kmhr. What are the upstream and downstream speeds respectively?
17-x, 17+x
When a boat goes with the stream (downstream) the stream and boat speeds, add up because stream helps boat move faster.
Hence, downstream speed = 17 + x
When the boat goes against the stream (upstream), the stream slows boat down. Hence, the stream reduces boat’s speed.
Hence upstream speed = 17-x