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    Question

    Ravi appointed 24 workers to finish a job in 18 days.

    After 9 days, he saw that only 1/3 of the job was completed. If 'n' is the number of additional workers required to complete the work on time, how many prime numbers are there which are less than or equal to (n/2)?
    A 10 Correct Answer Incorrect Answer
    B 8 Correct Answer Incorrect Answer
    C 18 Correct Answer Incorrect Answer
    D 5 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ,

    Work done = 24 × 9 × 10 = 2160 Only 1/3 of work done, so total work = 2160 × 3 = 6480 Remaining work = 6480 – 2160 = 4320 Time left = 9 days Let additional men = n ⇒ total men = 24 + n (24 + n) × 9 × 10 = 4320 ⇒ (24 + n) × 90 = 4320 ⇒ 24 + n = 48 ⇒ n = 24 Then, n/2 = 12 Prime numbers ≤ 12: 2, 3, 5, 7, 11 Total = 5 prime numbers

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