Question

    Four machine makes a beep after every 1, 3, 5 and2 min

    respectively . In 5hrs , how many times do they beep together if they have just beeped together.
    A 8 times Correct Answer Incorrect Answer
    B 10 times Correct Answer Incorrect Answer
    C 12 times Correct Answer Incorrect Answer
    D 14 times Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    LCM of 1, 3, 5 and 2 = 30 That means after 30 min they will beep again together. 30 min = 30/60 hrs = 1/2 [endif]-->hrs Then number of beep in 5hrs = (5 × 2)/1 = 10 times

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