What is upstream and downstream.explain it …

There are a variety of subconcepts which are related to answering questions based on boat and streams. Given below are the four terms which are important for a candidate to know to understand the concept of streams.

• Stream – The moving water in a river is called stream. 
• Upstream – If the boat is flowing in the opposite direction to the stream, it is called upstream. In this case, the net speed of the boat is called the upstream speed
• Downstream – If the boat is flowing along the direction of the stream, it is called downstream. In this case, the net speed of the boat is called downstream speed
• Still Water – Under this circumstance the water is considered to be stationary and the speed of the water is zero

The terms upstream and downstream oil and gas production refer to an oil or gas company's location in the supply chain. Upstream oil and gas production is conducted by companies who identify, extract, or produce raw materials. Downstream oil and gas production companies are closer to the end user or consumer.

When a boat travels in the same direction as the current, we say that it is traveling downstream. Thus if b is the speed of the boat in still water, and c is the speed of the current, then its total speed is. Downstream speed = b + c. When a boat travels against the current, it travels upstream.