New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    What is the speed of the stream if a ship takes 15 hours

    to travel 240 km in calm waters, given that the ratio of its speed against the current to its speed with the current is 5:11, respectively?
    A 12 km/h Correct Answer Incorrect Answer
    B 6 km/h Correct Answer Incorrect Answer
    C 25 km/h Correct Answer Incorrect Answer
    D 10 km/h Correct Answer Incorrect Answer
    E 8 km/h Correct Answer Incorrect Answer

    Solution

    ATQ, Let the upstream speed of the ship be '5a' km/h So, downstream speed of the Ship = 5a × (11/5) = '11a' km/h So, speed of the Ship in still water = 240 ÷ 15 = 16 km/h Let the speed of the stream be 'b' km/h ATQ; 5a + b = 11a - b Or, 2b = 6a So, b = 3a So, speed of the boat in still water = 11a - 3a Or, 16 = 8a So, a = 2 So, speed of the stream = 3a = 2 × 3 = 6 km/h

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