A boat covers 64 km upstream in 8 hrs and 120 km downstream in 12 hours. What is the speed ( in m/s) of the boat in still water?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 2.5
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Understanding |
Application |
Calculation |
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Boat covers 64 km upstream in 8 hours. |
Upstream speed = 8 km/hr |
⇒ 64/8 = 8
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Boat covers 120 km downstream in 12 hours. |
Downstream speed = 10 km/hr |
⇒ 120/12 = 10
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Suppose; Speed of boat = x Speed of water = y |
So, x – y = 8 and x + y = 10 Solving the equation: ⇒ x = 9 & y = 1 |
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Hence, Speed of boat in still water = 2.5 m/s |
⇒ 9 × 5/18 ⇒ 2.5 |