A boat can travel 40 km upstream in 8 hours. If the speed of the stream is 2 km/

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Question: A boat can travel 40 km upstream in 8 hours. If the speed of the stream is 2 km/h, what is the speed of the boat in still water?

Options:

Correct Answer: 8 km/h

Solution:

Let the speed of the boat in still water be y km/h. Upstream speed = (y - 2) km/h. Therefore, (y - 2) * 8 = 40. Solving gives y = 8 km/h.

A boat can travel 40 km upstream in 8 hours. If the speed of the stream is 2 km/h, what is the speed of the boat in still water?

A boat can travel 40 km upstream in 8 hours. If the speed of the stream is 2 km/h, what is the speed of the boat in still water?

Correct Answer: 8 km/h

Step 1: Understand that the boat travels upstream against the current of the stream.
Step 2: The speed of the stream is given as 2 km/h.
Step 3: Let the speed of the boat in still water be represented as 'y' km/h.
Step 4: When the boat is going upstream, its effective speed is reduced by the speed of the stream. So, the upstream speed is (y - 2) km/h.
Step 5: We know the boat travels 40 km upstream in 8 hours. We can use the formula: Distance = Speed × Time.
Step 6: Substitute the values into the formula: 40 km = (y - 2) km/h × 8 hours.
Step 7: Simplify the equation: 40 = 8(y - 2).
Step 8: Divide both sides by 8 to isolate (y - 2): 5 = y - 2.
Step 9: Add 2 to both sides to solve for y: y = 5 + 2.
Step 10: Therefore, y = 7 km/h, which is the speed of the boat in still water.

Relative Speed – Understanding how the speed of a boat is affected by the current of the stream when traveling upstream.
Algebraic Manipulation – Solving equations to find the unknown variable, in this case, the speed of the boat in still water.