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

    Question

    Ajay, Bjay, and Cheetna can individually finish a task

    in 20, 24, and 30 days, respectively. They began working together, but Ajay left the task 10 days before its completion, and Bijay left 4 days after Ajay's departure., then in how many days were needed to finish the entire task?
    A 25 days Correct Answer Incorrect Answer
    B 20 days Correct Answer Incorrect Answer
    C 14 days Correct Answer Incorrect Answer
    D 18 days Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ, Let total amount of task to be done = 120 units (LCM of 20, 24 and 30) Efficiency of Ajay = 120/20 = 6 units per day Efficiency of Bjay = 120/24 = 5 units per day Efficiency of Cheetna = 120/30 = 4 units per day Let total task is to be completed in ‘d’ days According to question; 6 × (d – 10) + 5 × (d – 6) + 4 × d = 120 Or, 6d + 5d + 4d = 120 + 60 + 30 = 210 Or, 15d = 210 So, d = 210/15 = 14 days

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